Handling Interrupts from a Virtual Function in a System with a Reconfigurable Processor

ABSTRACT

A system is presented that includes a communication link, a runtime processor coupled to the communication link, and a reconfigurable processor. The reconfigurable processor is adapted for generating an interrupt to the runtime processor in response to a predetermined event and includes multiple arrays of coarse-grained reconfigurable (CGR) units and an interface to the communication link that couples the reconfigurable processor to the runtime processor via the communication link. The runtime processor is adapted for configuring the interface to the communication link to provide access to the multiple arrays of coarse-grained reconfigurable units from a physical function driver and from at least one virtual function driver, and the reconfigurable processor is adapted for sending the interrupt to the physical function driver and to a virtual function driver of the at least one virtual function driver within the runtime processor.

RELATED APPLICATIONS AND DOCUMENTS

This application is a continuation application of co-pending, commonly-assigned U.S. patent application Ser. No. 18/104,758, entitled, “Configurable Access to a Reconfigurable Processor by a Virtual Function,” (Attorney Docket No. SBNV1065USN01), filed on Feb. 1, 2023, which claims the benefit of U.S. Provisional Patent Application No. 63/305,956, entitled, “Configurable Virtual Function” filed on 2 Feb. 2022. The priority application and the provisional application are hereby incorporated by reference herein in their entirety for all purposes.

This application also is related to the following papers and commonly owned applications:

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No. 17/185,264, filed     Feb. 25, 2021, entitled “TIME-MULTIPLEXED USE OF RECONFIGURABLE     HARDWARE;” -   U.S. Nonprovisional patent application Ser. No. 17/216,647, now U.S.     Pat. No. 11,204,889 B1, filed Mar. 29, 2021, entitled “TENSOR     PARTITIONING AND PARTITION ACCESS ORDER;” -   U.S. Nonprovisional patent application Ser. No. 17/216,650, now U.S.     Pat. No. 11,366,783 B1, filed Mar. 29, 2021, entitled “MULTI-HEADED     MULTI-BUFFER FOR BUFFERING DATA FOR PROCESSING;” -   U.S. Nonprovisional patent application Ser. No. 17/216,657, now U.S.     Pat. No. 11,263,170 B1, filed Mar. 29, 2021, entitled “LOSSLESS     TILING IN CONVOLUTION NETWORKS—PADDING BEFORE TILING, LOCATION-BASED     TILING, AND ZEROING-OUT;” -   U.S. Nonprovisional patent application Ser. No. 17/384,515, filed     Jul. 23, 2021, entitled “LOSSLESS TILING IN CONVOLUTION     NETWORKS—MATERIALIZATION OF TENSORS;” -   U.S. Nonprovisional patent application Ser. No. 17/216,651, now U.S.     Pat. No. 11,195,080 B1, filed Mar. 29, 2021, entitled “LOSSLESS     TILING IN CONVOLUTION NETWORKS—TILING CONFIGURATION;” -   U.S. Nonprovisional patent application Ser. No. 17/216,652, now U.S.     Pat. No. 11,227,207 B1, filed Mar. 29, 2021, entitled “LOSSLESS     TILING IN CONVOLUTION NETWORKS—SECTION BOUNDARIES;” -   U.S. Nonprovisional patent application Ser. No. 17/216,654, now U.S.     Pat. No. 11,250,061 B1, filed Mar. 29, 2021, entitled “LOSSLESS     TILING IN CONVOLUTION NETWORKS—READ-MODIFY-WRITE IN BACKWARD PASS;” -   U.S. Nonprovisional patent application Ser. No. 17/216,655, now U.S.     Pat. No. 11,232,360 B1, filed Mar. 29, 2021, entitled “LOSSLESS     TILING IN CONVOLUTION NETWORKS—WEIGHT GRADIENT CALCULATION;” -   U.S. Nonprovisional patent application Ser. No. 17/364,110, filed     Jun. 30, 2021, entitled “LOSSLESS TILING IN CONVOLUTION     NETWORKS—TILING CONFIGURATION FOR A SEQUENCE OF SECTIONS OF A     GRAPH;” -   U.S. Nonprovisional patent application Ser. No. 17/364,129, filed     Jun. 30, 2021, entitled “LOSSLESS TILING IN CONVOLUTION     NETWORKS—TILING CONFIGURATION BETWEEN TWO SECTIONS;” -   “U.S. Nonprovisional patent application Ser. No. 17/364,141, filed     Jun. 30, 2021, entitled ““LOSSLESS TILING IN CONVOLUTION     NETWORKS—PADDING AND RE-TILLING AT SECTION BOUNDARIES;” -   U.S. Nonprovisional patent application Ser. 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No. 17/397,241, now U.S.     Pat. No. 11,429,349 B1, filed Aug. 9, 2021, entitled “FLOATING POINT     MULTIPLY-ADD, ACCUMULATE UNIT WITH CARRY-SAVE ACCUMULATOR;” -   U.S. Nonprovisional patent application Ser. No. 17/216,509, now U.S.     Pat. No. 11,191,182 B1, filed Mar. 29, 2021, entitled “UNIVERSAL     RAIL KIT;” -   U.S. Nonprovisional patent application Ser. No. 17/379,921, now U.S.     Pat. No. 11,392,740 B2, filed Jul. 19, 2021, entitled “DATAFLOW     FUNCTION OFFLOAD TO RECONFIGURABLE PROCESSORS;” -   U.S. Nonprovisional patent application Ser. No. 17/379,924, now U.S.     Pat. No. 11,237,880 B1, filed Jul. 19, 2021, entitled “DATAFLOW     ALL-REDUCE FOR RECONFIGURABLE PROCESSOR SYSTEMS;” -   U.S. Nonprovisional patent application Ser. No. 17/378,342, now U.S.     Pat. No. 11,556,494 B1, filed Jul. 16, 2021, entitled “DEFECT REPAIR     FOR A RECONFIGURABLE DATA PROCESSOR;” -   U.S. Nonprovisional patent application Ser. No. 17/378,391, now U.S.     Pat. 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No. 11,239,846 B1, filed Jun. 3, 2021, entitled     “VARIABLE-LENGTH CLOCK STRETCHER WITH CORRECTION FOR GLITCHES DUE TO     PHASE DETECTOR OFFSET;” -   U.S. Nonprovisional patent application Ser. No. 17/338,626, now U.S.     Pat. No. 11,290,113 B1, filed Jun. 3, 2021, entitled     “VARIABLE-LENGTH CLOCK STRETCHER WITH CORRECTION FOR DIGITAL DLL     GLITCHES;” -   U.S. Nonprovisional patent application Ser. No. 17/338,629, now U.S.     Pat. No. 11,290,114 B1, filed Jun. 3, 2021, entitled     “VARIABLE-LENGTH CLOCK STRETCHER WITH PASSIVE MODE JITTER     REDUCTION;” -   U.S. Nonprovisional patent application Ser. No. 17/405,913, now U.S.     Pat. No. 11,334,109 B1, filed Aug. 18, 2021, entitled     “VARIABLE-LENGTH CLOCK STRETCHER WITH COMBINER TIMING LOGIC;” -   U.S. Provisional Patent Application No. 63/230,782, filed Aug. 8,     2021, entitled “LOW-LATENCY MASTER-SLAVE CLOCKED STORAGE ELEMENT;” -   U.S. Provisional Patent Application No. 63/236,218, filed Aug. 23,     2021, entitled “SWITCH FOR A RECONFIGURABLE DATAFLOW PROCESSOR;” -   U.S. Provisional Patent Application No. 63/236,214, filed Aug. 23,     2021, entitled “SPARSE MATRIX MULTIPLIER;” -   U.S. Provisional Patent Application No. 63/389,767, filed Jul. 15,     2022, entitled “PEER-TO-PEER COMMUNICATION BETWEEN RECONFIGURABLE     DATAFLOW UNITS;” -   U.S. Provisional Patent Application No. 63/405,240, filed Sep. 9,     2022, entitled “PEER-TO-PEER ROUTE THROUGH IN A RECONFIGURABLE     COMPUTING SYSTEM.”     All of the related application(s) and documents listed above are     hereby incorporated by reference herein for all purposes.

FIELD OF THE TECHNOLOGY DISCLOSED

The present technology relates to a data processing system, and more particularly, to a data processing system that handles configurable virtual functions. Such a data processing system includes a communication link, a runtime processor that is operatively coupled to the communication link, and one or more reconfigurable processors.

BACKGROUND

The subject matter discussed in this section should not be assumed to be prior art merely as a result of its mention in this section. Similarly, a problem mentioned in this section or associated with the subject matter provided as background should not be assumed to have been previously recognized in the prior art. The subject matter in this section merely represents different approaches, which in and of themselves can also correspond to implementations of the claimed technology.

Reconfigurable processors, including FPGAs, can be configured to implement a variety of functions more efficiently or faster than might be achieved using a general-purpose processor executing a computer program. So-called coarse-grained reconfigurable architectures (CGRAs) are being developed in which the configurable units in the array are more complex than used in typical, more fine-grained FPGAs, and may enable faster or more efficient execution of various classes of functions. For example, CGRAs have been proposed that can enable implementation of low-latency and energy-efficient accelerators for machine learning and artificial intelligence workloads.

Virtualization has enabled the efficient scaling and sharing of compute resources in the cloud, adapting to changing user needs at runtime. Users are offered a view of an application service with management of resources hidden from view, or alternatively abstracted development platforms for deploying applications that can adapt to changing needs. The flexibility, scalability, and affordability offered by cloud computing are fundamental to the massively connected compute paradigm of the future.

Furthermore, applications are migrating to the cloud in search of scalability, resilience, and cost-efficiency. Cloud providers typically offer support for new specialized hardware accelerators such as tensor processing units (TPUs) and intelligence processing units (IPUs), and on-demand graphics processing units (GPUs) and field programmable gate arrays (FPGAs). Such accelerators have driven the success of emerging application domains in the cloud, but cloud computing and hardware specialization are on a collision course.

In recent years, reconfigurable processors have emerged as a contender for cloud accelerators.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to like parts throughout the different views. Also, the drawings are not necessarily to scale, with an emphasis instead generally being placed upon illustrating the principles of the technology disclosed. In the following description, various implementations of the technology disclosed are described with reference to the following drawings.

FIG. 1 is a diagram of an illustrative data processing system including a reconfigurable processor, external memory, and a runtime processor.

FIG. 2 is a diagram of an illustrative reconfigurable processor with a memory interface, an input-output (10) interface, and arrays of coarse-grained reconfigurable (CGR) arrays.

FIG. 3 is a diagram of an illustrative reconfigurable processor including a top-level network (TLN) and two CGR arrays.

FIG. 4 is a diagram of an illustrative CGR array including CGR units and an array-level network (ALN).

FIG. 5 illustrates an example of a pattern memory unit (PMU) and a pattern compute unit (PCU), which may be combined in a fused-control memory unit (FCMU).

FIG. 6 is a diagram of an illustrative data processing system in which applications are provided a unified interface to a pool of reconfigurable data flow resources such that the pool of reconfigurable data flow resources is available to the applications as a single reconfigurable processor.

FIG. 7 is a diagram of an illustrative implementation of an execution file used by the technology disclosed to execute the applications on arrays of CGR units.

FIG. 8A is a diagram of an illustrative configuration in which four virtual functions are each assigned one array of CGR units.

FIG. 8B is a diagram of an illustrative configuration in which two virtual functions are each assigned two vertically arranged arrays of CGR units.

FIG. 8C is a diagram of an illustrative configuration in which two virtual functions are each assigned two horizontally arranged arrays of CGR units.

FIG. 8D is a diagram of an illustrative configuration in which a virtual function is assigned four arrays of CGR units.

FIG. 9 is a diagram of illustrative virtualization mailboxes between a physical function and virtual functions.

FIG. 10 is a diagram of an illustrative programming of base address registers (BARs) for virtual functions that are assigned arrays of CGR units.

FIG. 11 is a diagram of an illustrative interrupt that is generated by the reconfigurable processor in response to a predetermined event.

FIG. 12 is a flowchart showing illustrative operations that a runtime processor of a data processing system may perform for enabling virtual functions in a reconfigurable processor.

FIG. 13 is a flowchart showing illustrative operations that a runtime processor of a data processing system may perform for handling interrupts when virtual functions are enabled in a reconfigurable processor.

DETAILED DESCRIPTION

The following discussion is presented to enable any person skilled in the art to make and use the technology disclosed and is provided in the context of a particular application and its requirements. Various modifications to the disclosed implementations will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other implementations and applications without departing from the spirit and scope of the technology disclosed. Thus, the technology disclosed is not intended to be limited to the implementations shown but is to be accorded the widest scope consistent with the principles and features disclosed herein.

Reconfigurable processors combine significant computational capabilities with an architecture more amenable to virtualization and a lower power footprint. A key strength of reconfigurable processors is the ability to modify their operation at runtime, as well as the ease with which they can be safely partitioned for sharing. Reconfigurable processors, including FPGAs, can be configured to implement a variety of functions more efficiently or faster than might be achieved using a general-purpose processor executing a computer program.

So-called coarse-grained reconfigurable architectures (CGRAs) are being developed in which the configurable units in the array are more complex than used in typical, more fine-grained FPGAs, and may enable faster or more efficient execution of various classes of functions. For example, CGRAs have been proposed that can enable implementation of low-latency and energy-efficient accelerators for machine learning and artificial intelligence workloads.

As deep learning accelerators, reconfigurable processors are optimized to provide high performance for single-task and static-workload scenarios, which conflict with the multi-tenancy and dynamic resource allocation requirements of cloud computing.

Cloud applications typically run on virtual infrastructure, but practical virtualization support for accelerators has yet to arrive. Cloud providers routinely support accelerators but do so using Peripheral Component Interconnect Express (PCIe) pass-through techniques that dedicate physical hardware to virtual machines (VMs). Multi-tenancy and consolidation are lost as a consequence, which leads to hardware underutilization.

In fact, practical virtualization should support sharing and isolation under flexible policy with minimal overhead. The structure of accelerator stacks makes this combination extremely difficult to achieve. Historically, accelerator stacks are silos comprising proprietary layers communicating through memory mapped interfaces. This opaque organization makes it impractical to interpose intermediate layers to form an efficient and compatible virtualization boundary. The remaining interposable interfaces leave designers with untenable alternatives that sacrifice critical virtualization properties such as interposition and compatibility.

It is desirable therefore to provide virtual function support for reconfigurable processors that support multi-client and dynamic-workload scenarios. Runtime support for executing virtual functions on reconfigurable processors is needed that supports sharing and isolation with minimal overhead.

A technology is described which enables the execution of two or more applications on one or more reconfigurable processor while ensuring isolation between the two applications.

Traditional compilers translate human-readable computer source code into machine code that can be executed on a Von Neumann computer architecture. In this architecture, a processor serially executes instructions in one or more threads of software code. The architecture is static and the compiler does not determine how execution of the instructions is pipelined, or which processor or memory takes care of which thread. Thread execution is asynchronous, and safe exchange of data between parallel threads is not supported.

High-level programs for machine learning (ML) and artificial intelligence (AI) may require massively parallel computations, where many parallel and interdependent threads (meta-pipelines) exchange data. Such programs are ill-suited for execution on Von Neumann computers. They require architectures that are optimized for parallel processing, such as coarse-grained reconfigurable architectures (CGRAs) or graphic processing units (GPUs). The ascent of ML, AI, and massively parallel architectures places new requirements on compilers, including how computation graphs, and in particular data flow graphs, are pipelined, which operations are assigned to which compute units, how data is routed between various compute units and memory, and how synchronization is controlled, particularly when a data flow graph includes one or more nested loops, whose execution time varies dependent on the data being processed.

The architecture, configurability, and data flow capabilities of an array of coarse-grained reconfigurable (CGR) units enable increased compute power that supports both parallel and pipelined computation. A CGR processor, which includes one or more CGR arrays (arrays of CGR units), can be programmed to simultaneously execute multiple independent and interdependent data flow graphs. To enable simultaneous execution, the data flow graphs may be distilled from a high-level program and translated to a configuration file for the CGR processor. A high-level program is source code written in programming languages like Spatial, Python, C++, and C, and may use computation libraries for scientific computing, ML, AI, and the like. The high-level program and referenced libraries can implement computing structures and algorithms of machine learning models like AlexNet, VGG Net, GoogleNet, ResNet, ResNeXt, RCNN, YOLO, SqueezeNet, SegNet, GAN, BERT, ELMo, USE, Transformer, and Transformer-XL.

Translation of high-level programs to executable bit files is performed by a compiler. While traditional compilers sequentially map operations to processor instructions, typically without regard to pipeline utilization and duration (a task usually handled by the hardware), an array of CGR units requires mapping operations to processor instructions in both space (for parallelism) and time (for synchronization of interdependent computation graphs or data flow graphs). This requirement implies that a compiler for a CGRA must decide which operation of a computation graph or data flow graph is assigned to which of the CGR units, and how both data and, related to the support of data flow graphs, control information flows among CGR units, and to and from external hosts and storage.

FIG. 1 illustrates an example system 100 including a CGR processor 110, a runtime processor 180, and a memory 190. As shown, CGR processor 110 has a coarse-grained reconfigurable architecture (CGRA) and includes arrays of CGR units 120 such as CGR arrays.

Illustratively, CGR processor 110 may include bus interfaces. The bus interfaces may include peripheral component interconnect express (PCIe) channels, direct memory access (DMA) channels, and/or double data rate (DDR) channels, and/or network access channels such as InfiniBand (IB) or Ethernet channels.

As shown in FIG. 1 , CGR processor 110 may include a communication link interface (e.g., 10 interface 138) and a memory interface 139. Array of CGR units 120 may be coupled with IO interface 138 and memory interface 139 via databus 130 which may be part of a top-level network (TLN). Runtime processor 180 communicates with IO interface 138 via a communication link 185, and memory interface 139 communicates with memory 190 via a memory link 195.

An array of CGR units 120 may include control and status registers, compute units and memory units that are interconnected with an array-level network (ALN) to provide the circuitry for execution of a computation graph or a data flow graph that may have been derived from a high-level program with user algorithms and functions. The high-level program may include a set of procedures, such as learning or inferencing in an AI or ML system. More specifically, the high-level program may include applications, graphs, application graphs, user applications, computation graphs, control flow graphs, data flow graphs, models, deep learning applications, deep learning neural networks, programs, program images, jobs, tasks and/or any other procedures and functions that may perform serial and/or parallel processing. In some implementations, execution of the graph(s) may involve using more than one CGR processor 110.

CGR processor 110 may accomplish computational tasks by executing a configuration file (e.g., a processor-executable format (PEF) file). For the purposes of this description, a configuration file corresponds to a data flow graph, or a translation of a data flow graph, and may further include initialization data. A compiler compiles the high-level program to provide the configuration file. In some implementations described herein, a CGR array 120 is configured by programming one or more configuration stores with all or parts of the configuration file. Therefore, the configuration file is sometimes also referred to as a programming file.

A single configuration store may be at the level of the CGR processor 110 or the CGR array 120, or a CGR unit may include an individual configuration store. The configuration store may include configuration and status registers (CSRs). The CSRs may be divided into a predetermined number of memory blocks having a predetermined size. If desired, the CSRs in each CGR array 120 of the CGR processor 110 may be organized in one or more memory blocks. As an example, each CGR array 120 in the CGR processor 110 may include one memory block for the CSRs. As another example, each CGR array 120 in the CGR processor 110 may include two memory blocks for the CSRs. If desired, switches within a CGR array 120 or between CGR arrays 120 of the CGR processor 110 may include CSRs.

The configuration file may include configuration data for the CGR array and CGR units in the CGR array, and link the computation graph to the CGR array. Execution of the configuration file by CGR processor 110 causes the CGR array(s) to implement the user algorithms and functions in the data flow graph.

CGR processor 110 can be implemented on a single integrated circuit (IC) die or on a multichip module (MCM). An IC can be packaged in a single chip module or a multichip module. An MCM is an electronic package that may comprise multiple IC dies and other devices, assembled into a single module as if it were a single device. The various dies of an MCM may be mounted on a substrate, and the bare dies of the substrate are electrically coupled to the surface or to each other using for some examples, wire bonding, tape bonding or flip-chip bonding.

Runtime processor 180 may be, or be included in, a computer or host. Thus, runtime processor 180 may be a host or computer that executes runtime processes, as further referenced herein. If desired, the runtime processor may be configured with logic that implements runtime processes.

As mentioned above, the interface to the communication link 138 is operatively coupled to the communication link 185, thereby coupling the CGR processor 110 to the runtime processor 180 via the communication link 185.

Illustratively, the runtime processor 180 is adapted for configuring the interface 138 to the communication link 185 to provide access to the arrays of CGR units 120 through the communication link 185 from a physical function driver 183 and from at least one virtual function driver 186. In some implementations, the runtime processor 180 may be adapted for configuring the interface 138 to the communication link 185 to provide access to the arrays of CGR units 120 through the communication link 185 from a physical function driver 183 only. In these implementations, no virtual function may be enabled. A physical function 195 that is associated with the physical function driver 183 has exclusive access to a first portion of the at least one array of coarse-grained reconfigurable units 195, and the physical function 195 shares access to a second portion of the at least one array of coarse-grained reconfigurable units that is different than the first portion with at least one virtual function 196 that is associated with the virtual function driver 186.

In some implementations, the CGR processor 110 may be adapted for generating an interrupt 181 to the runtime processor 180 in response to a predetermined event. For example, the predetermined event may include at least one of a load-complete event, an execution-complete event, a checkpoint event, a direct memory access (DMA) completion event, a DMA error event, a memory access error, or a runtime exception.

The CGR processor 110 may configure delivery of the interrupt 181 for physical function driver 183 and virtual function driver 186. The CGR processor 110 may route the interrupt 181 to the appropriate physical function driver 183 and/or virtual function driver 186 based on the event generating the interrupt 181, the portion of the CGR processor 110 detecting or reporting the event, and the configuration of the virtual functions 196, 197 (e.g., the number of enabled VFs and their binding to the portions of the reconfigurable processor 110).

By way of example, the CGR processor 110 may include N arrays of CGR units 120, where N is an integer greater than 1. For example, CGR processor 110 may include two arrays of CGR units, three arrays of CGR units, four arrays of CGR units, or more than four arrays of CGR units, if desired.

Consider the scenario in which the CGR processor 110 includes N arrays of CGR units 120. In such a scenario, the runtime processor 180 may be adapted for configuring the interface to the communication link 138 to provide access to the N arrays of CGR units to the physical function driver 183 and to up to N virtual function drivers 186 that are each associated with a virtual function 196 on the CGR processor 110. In some implementations, the runtime processor 180 may enable as many virtual functions 196, 197 on the CGR processor 110 as the CGR processor 110 includes arrays of CGR units 120.

In this scenario, each virtual function of the up to N virtual functions may have exclusive access among the up to N virtual functions to at least one of the N arrays of CGR units 120. For example, the CGR processor 110 may have four arrays of CGR units 120. In this example, the runtime processor 180 may enable four virtual functions, whereby each virtual function has exclusive access among the four virtual functions to one array of CGR units 120, which the other three virtual functions are prevented from accessing.

FIG. 2 is a diagram of an illustrative reconfigurable processor 200. Reconfigurable processor 200 may include a memory interface 239, an input-output (10) interface 238, and arrays of coarse-grained reconfigurable (CGR) arrays 211, 212, 213, 214.

As shown in FIG. 2 , the reconfigurable processor 200 may include four arrays of CGR units 211, 212, 213, 214. The arrays of CGR units 211, 212, 213, 214 may be coupled with each other, with IO interface 238 and with memory interface 239 via databus 230 which may be part of a top-level network (TLN).

Each one of the four arrays of CGR units 211, 212, 213, 214 may include control and status registers, compute units, memory units, and an array-level network that couples the control and status registers, the compute units, and the memory units.

FIG. 3 illustrates example details of a CGR processor 300 including a top-level network (TLN 330) and two CGR arrays (CGR array 310 and CGR array 320). A CGR array comprises an array of CGR units (e.g., pattern memory units (PMUs), pattern compute units (PCUs), fused-control memory units (FCMUs)) coupled via an array-level network (ALN). The ALN may be coupled with the TLN 330 through several Address Generation and Coalescing Units (AGCUs), and consequently with input/output (I/O) interface 338 (or any number of interfaces) and memory interface 339. Other implementations may use different bus or communication architectures.

Circuits on the TLN in this example include one or more external I/O interfaces, including I/O interface 338 and memory interface 339. The interfaces to external devices include circuits for routing data among circuits coupled with the TLN 330 and external devices, such as high-capacity memory, host processors including runtime processors, other CGR processors, FPGA devices, and so on, that may be coupled with the interfaces.

As shown in FIG. 3 , each CGR array 310, 320 has four AGCUs (e.g., MAGCU1, AGCU12, AGCU13, and AGCU14 in CGR array 310). However, a skilled person may appreciate that a CGR array may have a different number of AGCUs. The AGCUs interface the TLN to the ALNs and route data from the TLN to the ALN or vice versa.

One of the AGCUs in each CGR array in this example is configured to be a master AGCU (MAGCU), which includes an array configuration load/unload controller for the CGR array. Illustratively, more than one array configuration load/unload controller can be implemented, and one array configuration load/unload controller may be implemented by logic distributed among more than one AGCU.

As shown in FIG. 3 , the MAGCU1 includes a configuration load/unload controller for CGR array 310, and MAGCU2 includes a configuration load/unload controller for CGR array 320. Some implementations may include more than one array configuration load/unload controller. In other implementations, an array configuration load/unload controller may be implemented by logic distributed among more than one AGCU. In yet other implementations, a configuration load/unload controller can be designed for loading and unloading configuration of more than one CGR array. In further implementations, more than one configuration controller can be designed for configuration of a single CGR array. Also, the configuration load/unload controller can be implemented in other portions of the system, including as a stand-alone circuit on the TLN and the ALN or ALNs.

The TLN 330 may be constructed using top-level switches (e.g., switch 311, switch 312, switch 313, switch 314, switch 315, and switch 316). If desired, the top-level switches may be coupled with at least one other top-level switch. At least some top-level switches may be connected with other circuits on the TLN, including the AGCUs, and external I/O interface 338.

Illustratively, the TLN 330 includes links (e.g., L11, L12, L21, L22) coupling the top-level switches. Data may travel in packets between the top-level switches on the links, and from the switches to the circuits on the network coupled with the switches. For example, switch 311 and switch 312 are coupled by link L11, switch 314 and switch 315 are coupled by link L12, switch 311 and switch 314 are coupled by link L13, and switch 312 and switch 313 are coupled by link L21. The links can include one or more buses and supporting control lines, including for example a chunk-wide bus (vector bus). For example, the top-level network can include data, request and response channels operable in coordination for transfer of data in any manner known in the art.

FIG. 4 illustrates an example CGR array 400, including an array of CGR units in an ALN. CGR array 400 may include several types of CGR unit 401, such as FCMUs, PMUs, PCUs, memory units, and/or compute units. For examples of the functions of these types of CGR units, see Prabhakar et al., “Plasticine: A Reconfigurable Architecture for Parallel Patterns”, ISCA 2017, Jun. 24-28, 2017, Toronto, ON, Canada.

Illustratively, each of the CGR units may include a configuration store 402 comprising a set of registers or flip-flops storing configuration data that represents the setup and/or the sequence to run a program, and that can include the number of nested loops, the limits of each loop iterator, the instructions to be executed for each stage, the source of operands, and the network parameters for the input and output interfaces. In some implementations, each CGR unit 401 comprises an FCMU. In other implementations, the array comprises both PMUs and PCUs, or memory units and compute units, arranged in a checkerboard pattern. In yet other implementations, CGR units may be arranged in different patterns.

The ALN includes switch units 403 (S), and AGCUs (each including two address generators 405 (AG) and a shared coalescing unit 404 (CU)). Switch units 403 are connected among themselves via interconnects 421 and to a CGR unit 401 with interconnects 422. Switch units 403 may be coupled with address generators 405 via interconnects 420. In some implementations, communication channels can be configured as end-to-end connections.

A configuration file may include configuration data representing an initial configuration, or starting state, of each of the CGR units 401 that execute a high-level program with user algorithms and functions. Program load is the process of setting up the configuration stores 402 in the CGR array 400 based on the configuration data to allow the CGR units 401 to execute the high-level program. Program load may also require loading memory units and/or PMUs.

In some implementations, a runtime processor (e.g., runtime processor 180 of FIG. 1 ) may perform the program load.

The ALN may include one or more kinds of physical data buses, for example a chunk-level vector bus (e.g., 512 bits of data), a word-level scalar bus (e.g., 32 bits of data), and a control bus. For instance, interconnects 421 between two switches may include a vector bus interconnect with a bus width of 512 bits, and a scalar bus interconnect with a bus width of 32 bits. A control bus can comprise a configurable interconnect that carries multiple control bits on signal routes designated by configuration bits in the CGR array's configuration file. The control bus can comprise physical lines separate from the data buses in some implementations. In other implementations, the control bus can be implemented using the same physical lines with a separate protocol or in a time-sharing procedure.

Physical data buses may differ in the granularity of data being transferred. In one implementation, a vector bus can carry a chunk that includes 16 channels of 32-bit floating-point data or 32 channels of 16-bit floating-point data (i.e., 512 bits) of data as its payload. A scalar bus can have a 32-bit payload and carry scalar operands or control information. The control bus can carry control handshakes such as tokens and other signals. The vector and scalar buses can be packet-switched, including headers that indicate a destination of each packet and other information such as sequence numbers that can be used to reassemble a file when the packets are received out of order. Each packet header can contain a destination identifier that identifies the geographical coordinates of the destination switch unit (e.g., the row and column in the array), and an interface identifier that identifies the interface on the destination switch (e.g., North, South, East, West, etc.) used to reach the destination unit.

A CGR unit 401 may have four ports (as drawn) to interface with switch units 403, or any other number of ports suitable for an ALN. Each port may be suitable for receiving and transmitting data, or a port may be suitable for only receiving or only transmitting data.

A switch unit 403, as shown in the example of FIG. 4 , may have eight interfaces. The North, South, East and West interfaces of a switch unit may be used for links between switch units 403 using interconnects 421. The Northeast, Southeast, Northwest and Southwest interfaces of a switch unit 403 may each be used to make a link with an FCMU, PCU or PMU instance 401 using one of the interconnects 422. Two switch units 403 in each CGR array quadrant have links to an AGCU using interconnects 420. The coalescing unit 404 of the AGCU arbitrates between the AGs 405 and processes memory requests. Each of the eight interfaces of a switch unit 403 can include a vector interface, a scalar interface, and a control interface to communicate with the vector network, the scalar network, and the control network. In other implementations, a switch unit 403 may have any number of interfaces.

During execution of a graph or subgraph in a CGR array 400 after configuration, data can be sent via one or more switch units 403 and one or more links 421 between the switch units to the CGR units 401 using the vector bus and vector interface(s) of the one or more switch units 403 on the ALN. A CGR array may comprise at least a part of CGR array 400, and any number of other CGR arrays coupled with CGR array 400.

A data processing operation implemented by CGR array configuration may comprise multiple graphs or subgraphs specifying data processing operations that are distributed among and executed by corresponding CGR units (e.g., FCMUs, PMUs, PCUs, AGs, and CUs).

FIG. 5 illustrates an example 500 of a PMU 510 and a PCU 520, which may be combined in an FCMU 530. PMU 510 may be directly coupled to PCU 520, or optionally via one or more switches. PMU 510 includes a scratchpad memory 515, which may receive external data, memory addresses, and memory control information (e.g., write enable, read enable) via one or more buses included in the ALN. PCU 520 includes two or more processor stages, such as single instruction multiple datapath (SIMD) processor 521 through SIMD 526, and configuration store 528. The processor stages may include ALUs, or SIMDs, as drawn, or any other reconfigurable stages that can process data.

Each stage in PCU 520 may also hold one or more registers (not drawn) for short-term storage of parameters. Short-term storage, for example during one to several clock cycles or unit delays, allows for synchronization of data in the PCU pipeline.

FIG. 6 is a diagram of an illustrative data processing system 600 in which applications are provided a unified interface to a pool of reconfigurable data flow resources 678 such that the pool of reconfigurable data flow resources 678 is available to the applications as a single reconfigurable processor.

The pool of reconfigurable data flow resources 678 includes memory units (e.g., memory 190 of FIG. 1 ), busses (e.g., communication link 185, memory link 195, and/or TLN 130 of FIG. 1 ), and CGR arrays or arrays of CGR units (e.g., CGR arrays 120 of FIG. 1 ) that are connected with each other and with the memory units through the busses.

The busses or transfer resources enable the CGR arrays to receive and send data from and to devices outside the pool of reconfigurable data flow resources 678. Examples of the busses include Peripheral Component Interface Express (PCIe) channels, direct memory access (DMA) channels, double data-rate (DDR) channels, Ethernet channels, and InfiniBand™ channels. In some implementations, the busses include at least one of a DMA channel, a DDR channel, a PCIe channel, an Ethernet channel, or an InfiniBand channel.

The arrays of CGR units (e.g., compute units and memory units) are arranged in one or more reconfigurable processors (e.g., one or more of CGR processor 110 of FIG. 1 ) and may be coupled with each other in a programmable interconnect fabric. In some implementations, the arrays of CGR units are aggregated as a uniform pool of resources that are assigned to the execution of user applications.

The memory units of the pool of reconfigurable data flow resources 678 may be usable by the arrays of CGR units to store data. Examples of the memory units include main memory (e.g., off-chip/external dynamic random-access memory (DRAM)), local secondary storage (e.g., local disks (e.g., hard disk drive (HDD), solid-state drive (SSD))), and remote secondary storage (e.g., distributed file systems, web servers). Other examples of the memory units include PMUs, latches, registers, and caches (e.g., SRAM). In some implementations, the memory units include at least one of a DRAM, a HDD, a SSD, a distributed file system, or a web server.

The pool of reconfigurable data flow resources 678 is dynamically scalable to meet the performance objectives of applications (or user applications). In some implementations, the applications access the pool of reconfigurable data flow resources 678 over one or more networks (e.g., Internet).

The pool of reconfigurable data flow resources 678 may have different compute scales and hierarchies according to different implementations of the technology disclosed.

In one example, the pool of reconfigurable data flow resources 678 is a node (or a single machine) with CGR arrays that are arranged in a plurality of reconfigurable processors, supported by bus and memory units. The node also includes a host processor (e.g., CPU). The host processor includes a runtime processor 666 that manages resource allocation, memory mapping, and execution of the configuration files and execution files 656 for applications requesting execution from the host processor. The runtime processor 666 exchanges data with the plurality of reconfigurable processors (RP0, RP1, RP2, etc.), for example, over a communication link such as a PCIe bus 672.

In another example, the pool of reconfigurable data flow resources 678 is a rack (or cluster) of nodes, such that each node in the rack runs a respective plurality of reconfigurable processors, and includes a respective host processor configured with a respective runtime processor. The runtime processors are distributed across the nodes and communicate with each other so that they have unified access to the reconfigurable processors attached not just to their own node on which they run, but also to the reconfigurable processors attached to every other node in the data center.

The nodes in the rack are connected, for example, over Ethernet or InfiniBand (IB). In yet another example, the pool of reconfigurable data flow resources 678 is a pod that comprises a plurality of racks. In yet another example, the pool of reconfigurable data flow resources 678 is a superpod that comprises a plurality of pods. In yet another example, the pool of reconfigurable data flow resources 678 is a zone that comprises a plurality of superpods. In yet another example, the pool of reconfigurable data flow resources 678 is a data center that comprises a plurality of zones.

Users may execute applications on the compute environment 600. Therefore, applications are sometimes also referred to as user applications. The applications are executed on the pool of reconfigurable data flow resources 678 in a distributed fashion by programming the individual compute and memory components to asynchronously receive, process, and send data and control information.

The applications comprise high-level programs. A high-level program may include source code written in programming languages like C, C++, Java, JavaScript, Python, and/or Spatial, for example, using deep learning frameworks such as PyTorch, TensorFlow, ONNX, Caffe, and/or Keras. The high-level program can implement computing structures and algorithms of machine learning models like AlexNet, VGG Net, GoogleNet, ResNet, ResNeXt, RCNN, YOLO, SqueezeNet, SegNet, GAN, BERT, ELMo, USE, Transformer, and/or Transformer-XL.

Illustratively, a software development kit (SDK) generates computation graphs (e.g., data flow graphs, control graphs) of the high-level programs of the applications. A compiler may transform the computation graphs into a hardware-specific configuration, which is specified in an execution file 656 generated by the compiler.

In one implementation, the compiler partitions the computation graphs into memory allocations and execution fragments, and these partitions are specified in the execution file 656. Execution fragments represent operations on data. An execution fragment can comprise portions of a program representing an amount of work. An execution fragment can comprise computations encompassed by a set of loops, a set of graph nodes, or some other unit of work that requires synchronization. An execution fragment can comprise a fixed or variable amount of work, as intended by the program. Different ones of the execution fragments can contain different amounts of computation. Execution fragments can represent parallel patterns or portions of parallel patterns and are executable asynchronously.

Memory allocations represent the creation of logical memory spaces in on-chip and/or off-chip memories for data used to implement the computation graphs, and these memory allocations are specified in the execution file 656. Memory allocations define the type and the number of hardware resources (functional units, storage, or connectivity components). Main memory (e.g., DRAM) is off-chip memory for which the memory allocations can be made. Scratchpad memory (e.g., SRAM) is on-chip memory for which the memory allocations can be made. Other memory types for which the memory allocations can be made for various access patterns and layouts include read-only lookup-tables (LUTs), fixed size queues (e.g., FIFOs), and register files.

The compiler binds memory allocations to virtual memory units and binds execution fragments to virtual compute units, and these bindings are specified in the execution file 656. In some implementations, the compiler partitions execution fragments into memory fragments and compute fragments, and these partitions are specified in the execution file 656.

The compiler assigns the memory fragments to the virtual memory units and assigns the compute fragments to the virtual compute units, and these assignments are specified in the execution file 656. Each memory fragment is mapped operation-wise to the virtual memory unit corresponding to the memory being accessed. Each operation is lowered to its corresponding configuration intermediate representation for that virtual memory unit. Each compute fragment is mapped operation-wise to a newly allocated virtual compute unit. Each operation is lowered to its corresponding configuration intermediate representation for that virtual compute unit.

The compiler allocates the virtual memory units to physical memory units of a reconfigurable processor (e.g., pattern memory units (PMUs) of the reconfigurable processor) and allocates the virtual compute units to physical compute units of the reconfigurable processor (e.g., pattern compute units (PCUs) of the reconfigurable processor), and these allocations are specified in the execution file 656. The compiler places the physical memory units and the physical compute units onto positions in the arrays of CGR units of the pool of reconfigurable data flow resources 678 and routes data and control networks between the placed positions, and these placements and routes are specified in the execution file 656.

The compiler may translate the applications developed with commonly used open-source packages such as Keras and/or PyTorch into reconfigurable processor specifications. The compiler generates the configuration files with configuration data for the placed positions and the routed data and control networks. In one implementation, this includes assigning coordinates and communication resources of the physical memory and compute units by placing and routing units onto the arrays of the CGR units while maximizing bandwidth and minimizing latency.

Runtime processor 666 receives the execution file 656 from the SDK and uses the execution file 656 for resource allocation, memory mapping, and execution of the configuration files for the applications on the pool of reconfigurable data flow resources 678.

The execution file 656 may further include resource requests for transfer resources (e.g., PCIe channels, direct memory access (DMA) channels, double data rate (DDR) channels and/or network access channels) and storage resources (e.g., level 1 cache, level 2 cache, level 3 cache, main memory, local secondary storage, and/or remote secondary storage) required to satisfy data and control dependencies of the application graphs.

Furthermore, the runtime processor 666 is operatively coupled to the pool of reconfigurable data flow resources 678 (e.g., via communication link 672). If desired, the communication link may be a PCIe bus 672 or any other communication link that enables the runtime processor 666 to exchange data with the pool of reconfigurable data flow resources 678.

The runtime processor 666 parses the execution file 656, which includes a plurality of configuration files. Configuration files in the plurality of configurations files include configurations of the virtual data flow resources that are used to execute the user applications. The runtime processor 666 allocates a subset of the arrays of CGR units in the pool of reconfigurable data flow resources 678 to the virtual data flow resources.

The runtime processor 666 then loads the configuration files for the applications to the subset of the arrays of CGR units. In the scenario in which the execution file 656 includes two user applications (e.g., a first and a second user application), the runtime processor 666 is adapted for configuring the interface to the PCIe bus 672 to provide access to a first subset of the memory units and to a first subset of the arrays of CGR units in the pool of reconfigurable data flow resources 678 from a physical function driver and from a first virtual function driver and to provide access to a second subset of the memory units and to a second subset of the arrays of CGR units in the pool of reconfigurable data flow resources 678 from the physical function driver and from a second virtual function driver.

An application for the purposes of this description includes the configuration files for reconfigurable data flow resources in the pool of reconfigurable data flow resources 678 compiled to execute a mission function procedure or set of procedures using the reconfigurable data flow resources, such as inferencing or learning in an artificial intelligence or machine learning system. A virtual machine for the purposes of this description comprises a set of reconfigurable data flow resources (including arrays of CGR units in one or more reconfigurable processor, bus and memory units) configured to support execution of an application in arrays of CGR units and associated bus and memory units in a manner that appears to the application as if there were a physical constraint on the resources available, such as would be experienced in a physical machine. The virtual machine can be established as a part of the application of the mission function that uses the virtual machine, or it can be established using a separate configuration mechanism. In implementations described herein, virtual machines are implemented using resources of the pool of reconfigurable data flow resources 678 that are also used in the application, and so the configuration files for the application include the configuration data for its corresponding virtual machine, and links the application to a particular set of CGR units in the arrays of CGR units and associated bus and memory units.

The runtime processor 666 implements a first application in virtual machine VM1 that is allocated a particular set of reconfigurable data flow resources and implements a second application in virtual machine VM2 that is allocated another set of reconfigurable data flow resources. Virtual machine VM1 includes a particular set of CGR units, which can include some or all CGR units of a single reconfigurable processor or of multiple reconfigurable processors, along with associated bus and memory units (e.g., PCIe channels, DMA channels, DDR channels, DRAM memory). Virtual machine VM2 includes another set of CGR units, which can include some or all CGR units of a single reconfigurable processor or of multiple reconfigurable processors, along with associated bus and memory units (e.g., PCIe channels, DMA channels, DDR channels, DRAM memory).

Illustratively, CSRs of an example reconfigurable processor may be used for memory mapping virtual buffers in a virtual memory space to a physical memory space. CSRs in the allocated physical element may be used to map the application virtual buffer addresses to the appropriate physical addresses by having the runtime processor 666 program them.

In one implementation, the runtime processor 666 may configure CSRs of the reconfigurable processor(s) with configuration data (e.g., bit stream) identifying the mapping between the virtual address spaces and the physical address spaces for the configuration files to access the physical memory segments during execution of the applications.

Illustratively, the runtime processor 666 may allocate a memory region and create memory manager mappings. If desired, a first set of the physical memory segments mapped to buffers allocated to a first one of the applications are different from a second set of the physical memory segments mapped to buffers allocated to a second one of the applications. Also, access of the buffers allocated to the first one of the applications is confined to the first set of the physical memory segments, and access of the buffers allocated to the second one of the applications is confined to the second set of the physical memory segments.

The reconfigurable processor may provide several configurations for double data rate (DDR) and/or high bandwidth memory (HBM) access that define the memory access physical address map (i.e., memory access from the runtime processor 666 using the base address and memory access from the application).

As an example, consider the scenario in which each CGR array in a reconfigurable processor has a DDR interface and an HBM interface. Consider further that each CGR array is allocated to a different virtual function. In this scenario, a configuration may isolate the CGR arrays and thus the virtual functions in the reconfigurable processor from each other, and the virtual functions can access the DDR interface and the HBM interface connected to the local CGR array, but cannot access the DDR interfaces and the HBM interfaces connected to the other CGR arrays.

An alternative configuration may provide the physical function and the virtual functions access to the DDR interface and the HBM interface from two or more CGR arrays. As an example, in the alternative configuration, the physical function may partition the physical address map by interleaving DDR accesses with each CGR array, but may not interleave DDR accesses between the CGR arrays.

As another example, in the alternative configuration, the physical function may partition the physical address map by interleaving DDR accesses across the different CGR arrays.

If desired, a separate configuration may control the physical address map during HBM interleaving. For example, the HBM interleaving configuration may support interleaving within an HBM controller. However, disabling interleaving may facilitate restriction of memory access from a given CGR array to a single DDR or HBM interface.

If desired, controls other than interleaving are available that allow the PF to partition the physical address map dynamically between the VFs.

The reconfigurable processor may provide peer-to-peer (P2P) and P2P route-through capabilities that are operable between the CGR arrays for the physical function and the virtual functions. For more details on the P2P and P2P route-through capabilities, see U.S. Provisional Patent Application No. 63/389,767, entitled, “Peer-To-Peer Communication Between Reconfigurable Dataflow Units” and U.S. Provisional Patent Application No. 63/405,240, entitled, “Peer-To-Peer Route Through in a Reconfigurable Computing System.” For example, an AGCU of one CGR array (e.g., AGCU13 of CGR array 1 310 of FIG. 3 ) may need to send its P2P transaction to another CGR array (e.g., CGR array 2 320 of FIG. 3 ). The reconfigurable processor may support these accesses regardless of the CSR address map option implemented, and regardless of memory access map configuration. The physical function may use the AGCU Real to Physical Buffer (R2PB) to limit or control each virtual function's access to other CGR arrays and to a PCIe interfaces for P2P, if desired.

As an example, the address map may be implemented for each CGR array with no access to the other CGR arrays. Thus, the address map provides access to the resources on the respective CGR array, but provides no access to the CSRs on the other CGR arrays, for example by requiring R2PB entries.

As another example, the address map may be implemented for a single CGR array, and the single CGR array address map may be copied to each CGR array, and a CGR array identifier may statically map each CGR array to a portion of the overall address map. For example, if the reconfigurable processor includes two CGR arrays (e.g., CGR array 1 and CGR array 2 of FIG. 3 ), a lower power-of-two sized portion of the overall address (e.g., identified by a ‘0’ in the most significant bit (MSB)) map may be assigned to CGR array 1, and an upper power-of-two sized portion of the overall address map (e.g., identified by a ‘1’ in the MSB) may be assigned to CGR array 2. Consider the scenario in which CGR array 1 is assigned to virtual function VF1 and CGR array 2 to virtual function VF2. In this scenario, since the virtual functions VF1 and VF2 use virtualized addresses, there is no need for the virtual function to explicitly set the bit that identifies the lower and upper power-of-two sized portions of the overall address map. Instead, an interface between the runtime processor 666 and the reconfigurable processor in the pool of reconfigurable data flow resources 678 may adjust the virtualized addresses to address the correct CGR array, if desired. In this example, the physical function's addresses may not be virtualized. Therefore, the physical function driver (e.g., in the runtime processor 666) may know the addressed CGR array.

As yet another example, the address map may be arranged by distinguishing between a local CGR array and other CGR arrays, whereby the local CGR array has a host PCIe connection and the other CGR arrays have a host PCIe connection. In this example, the physical function driver (e.g., the runtime processor 666) may use virtualized CSR addresses. The single CGR array address map may be copied to each CGR array and provide relative addressing rather than absolute addressing. For example, if the reconfigurable processor includes two CGR arrays (e.g., local CGR array and other CGR array), a lower power-of-two sized portion of the overall address (e.g., identified by a ‘0’ in the most significant bit (MSB)) map may be assigned to the local CGR array, and an upper power-of-two sized portion of the overall address map (e.g., identified by a ‘1’ in the MSB) may be assigned to the other CGR array. Since the virtual functions use virtualized addresses, there is no need for the virtual function to explicitly set the bit that identifies the lower and upper power-of-two sized portions of the overall address map. Instead, an interface between the runtime processor 666 and the reconfigurable processor in the pool of reconfigurable data flow resources 678 may adjust the virtualized addresses to address the correct CGR array, if desired.

The runtime processor 666 respects the topology information (e.g., topology information 704 of FIG. 7 ) in the execution file 656 when allocating CGR units to the virtual data flow resources requested in the execution file 656. For example, consider the scenario in which the reconfigurable processor has a non-uniform communication bandwidth in East/West directions versus North/South directions. In this scenario, a virtual function that requires, for example, two CGR arrays arranged horizontally, may suffer in performance if mapped to a physical geometry in which two CGR arrays are arranged vertically. In some implementations, the topology information may specify rectilinear geometries.

As discussed above, the configurations of virtual data flow resources in the execution file 656 specify virtual memory segments for the reconfigurable data flow resources in the pool of reconfigurable data flow resources 678, including virtual address spaces of the virtual memory segments and sizes of the virtual address spaces. The runtime processor 666 maps the virtual address spaces of the virtual memory segments to physical address spaces of physical memory segments in the memory. The memory can be host memory, or device memory (e.g., off-chip DRAM).

The runtime processor 666 configures control and status registers of the reconfigurable data flow resources in the pool of reconfigurable data flow resources 678 with configuration data identifying the mapping between the virtual address spaces and the physical address spaces for the configuration files to access the physical memory segments during execution of the applications.

Turning to FIG. 7 , the illustrative execution file 656 includes configuration files (e.g., configuration files 722 a, 722 b, 722 n). The configuration files are sometimes also referred to as bit files 722 a, 722 b, 722 n that implement the computation graphs of the user applications using the arrays of CGR units and the bus and memory units in the pool of reconfigurable data flow resources 678 of FIG. 6 .

A program executable contains a bit-stream representing the initial configuration, or starting state, of each of the CGR units that execute the program. This bit-stream is referred to as a bit file, or hereinafter as a configuration file. The execution file 656 includes header 702 that indicates destinations on the reconfigurable processors for configuration data in the configuration files. In some implementations, a plurality of configuration files is generated for a single application.

The execution file 656 includes metadata 712 that accompanies the configuration files and specifies configurations of virtual data flow resources used to execute the applications. In one example, the execution file 656 can specify that a particular application uses an entire reconfigurable processor for execution, and as a result the metadata 712 identifies virtual data flow resources equaling at least the entire reconfigurable processor for loading and executing the configuration files for the particular application. In another example, the execution file 656 can specify that a particular application uses one or more portions of a reconfigurable processor for execution, and as a result the metadata 712 identifies virtual data flow resources equaling at least the one or more portions of the reconfigurable processor for loading and executing the configuration files for the particular application.

In yet another example, the execution file 656 can specify that a particular application uses an entire node for execution, and as a result the metadata 712 identifies virtual data flow resources equaling at least the entire node for loading and executing the configuration files for the particular application. In yet another example, the execution file 656 can specify that a particular application uses two or more nodes for execution, and as a result the metadata 712 identifies virtual data flow resources equaling at least the two or more nodes for loading and executing the configuration files for the particular application.

One skilled in the art would appreciate that the execution file 656 can similarly specify reconfigurable processors or portions thereof spanning across racks, pods, superpods, and zones in a data center, and as a result the metadata 712 identifies virtual data flow resources spanning across the racks, pods, superpods, and zones in the data center for loading and executing the configuration files for the particular application.

As part of the metadata 712, the execution file 656 includes topology information 704 that specifies orientation or shapes of portions of a reconfigurable processor for loading and executing the configuration files for a particular application.

In one implementation, a reconfigurable processor comprises a plurality of CGR arrays. Illustratively, a reconfigurable processor may include two CGR arrays (e.g., the CGR processor 300 of FIG. 3 ). If desired, a reconfigurable processor may include more than two CGR arrays. For example, a reconfigurable processor may include four, eight, or sixteen CGR arrays, or any other number of CGR arrays, including numbers that are not a power of two. The topology information 704 specifies an orientation of CGR arrays in the plurality of CGR arrays used to load and execute the configuration files for a particular application.

For example, when the reconfigurable processor includes four CGR arrays that are arranged in a two-by-two matrix and the particular application is allocated two CGR arrays of the reconfigurable processor, the topology information 704 specifies whether the two CGR arrays are arranged in a vertical orientation (2V) 716 or a horizontal orientation (2H) 726. The topology information 704 can also allocate a single CGR array (1T) 706 of the reconfigurable processor to the particular application. The topology information 704 can also allocate four CGR arrays (4T) 736 of the reconfigurable processor to the particular application. In other implementations, other geometries may be specified, such as a group of three CGR arrays.

The execution file 656 also specifies virtual flow resources like PCIe channels, DMA channels, and DDR channels used to load and execute the configuration files for a particular application. The execution file 656 also specifies virtual flow resources like main memory (e.g., off-chip/external DRAM), local secondary storage (e.g., local disks (e.g., HDD, SSD)), remote secondary storage (e.g., distributed file systems, web servers), latches, registers, and caches (e.g., SRAM) used to load and execute the configuration files for a particular application.

The execution file 656 also specifies virtual memory segments 714 for the requested virtual flow resources, including virtual address spaces of the virtual memory segments and sizes of the virtual address spaces. The execution file 656 also specifies symbols 724 (e.g., tensors, streams) used to load and execute the configuration files for a particular application. The execution file 656 also specifies HOST FIFOs 734 accessed by the configuration files for a particular application during execution. The execution file 656 also specifies peer-to-peer (P2P) streams 744 (e.g., data flow exchanges and control token exchanges between sources and sinks) exchanged between configurable units on which the configuration files for a particular application are loaded and executed. The execution file 656 also specifies arguments 754 that modify execution logic of a particular application by supplying additional parameters or new parameter values to the configuration files for the particular application. The execution file 656 also specifies functions 764 (e.g., data access functions like transpose, alignment, padding) to be performed by the configurable units on which the configuration files for a particular application are loaded and executed.

Illustratively, a reconfigurable processor may have four CGR arrays. For example, CGR processor 110 of FIG. 1 may have four CGR arrays 120. The reconfigurable processor may be configured to be under control of one physical function (e.g., PF 195 of FIG. 1 ). If desired, the reconfigurable processor may be configured to be under control of one or more virtual function (e.g., VF1 196 and/or VF2 197 of FIG. 1 ).

In some implementations, a runtime processor (e.g., runtime processor 180 of FIG. 1 ) may be adapted for configuring an interface to a communication link (e.g., I/O IF 138 of FIG. 1 ) that is operatively coupled to a communication link (e.g., communication link 185 of FIG. 1 ) between the reconfigurable processor and the runtime processor. If desired, the runtime processor may be adapted for configuring the interface to the communication link based at least in part on a number of virtual functions to enable and based on resource requirements of the virtual functions.

As an example, the runtime processor may be adapted for configuring the interface to the communication link according to a first configuration in which up to four virtual functions (e.g., VF1, VF2, VF3, and VF4) are enabled. Each one of the up to four virtual functions may be assigned a different CGR array.

The first configuration 822 in which four virtual functions VF1, VF2, VF3, and VF4 are each assigned a different CGR array of a reconfigurable processor 810 is illustratively shown in FIG. 8A. As shown in FIG. 8A, VF1 is assigned CGR array 832, VF2 is assigned CGR array 834, VF3 is assigned CGR array 836, and VF4 is assigned CGR array 838.

As another example, the runtime processor may be adapted for configuring the interface to the communication link according to a second configuration in which up to two virtual functions (e.g., VF1 and VF2) are enabled. Each one of the up to two virtual functions may be assigned two adjacent CGR arrays. If the reconfigurable processor has a two-by-two array of CGR arrays, a first virtual function VF1 may be assigned one vertical pair of CGR arrays, and the second virtual function VF2 may be assigned another vertical pair of CGR arrays of the reconfigurable processor 810 as illustratively shown in FIG. 8B. As shown in the configuration 824 of FIG. 8B, VF1 is assigned CGR arrays 842, and VF2 is assigned CGR arrays 844 of reconfigurable processor 810.

Alternatively, the first virtual function VF1 may be assigned one horizontal pair of CGR arrays, and the second virtual function VF2 may be assigned another horizontal pair of CGR arrays as illustratively shown in FIG. 8C. As shown in the configuration 826 of FIG. 8C, VF1 is assigned CGR arrays 854, and VF2 is assigned CGR arrays 852 of reconfigurable processor 810. If desired, the two virtual functions may be assigned two pairs of CGR arrays that are arranged non-adjacent to each other.

As yet another example, the runtime processor may be adapted for configuring the interface to the communication link according to a third configuration in which a single virtual function (e.g., VF1) is assigned the four CGR arrays of the reconfigurable processor as illustratively shown in FIG. 8D. As shown in the configuration 828 of FIG. 8D, VF1 is assigned CGR arrays 862 of reconfigurable processor 810.

As yet another example, the runtime processor may be adapted for configuring the interface to the communication link according to a fourth configuration in which a single virtual function (e.g., VF1) is assigned three CGR arrays of the reconfigurable processor. In this configuration, up to one additional virtual function may be assigned the fourth CGR array of the reconfigurable processor.

As yet another example, the runtime processor may be adapted for configuring the interface to the communication link according to a fifth configuration in which three virtual functions (VF1, VF2, VF3) are enabled, whereby one virtual function (e.g., VF1) is assigned two CGR arrays, and the two other virtual functions (e.g., VF2 and VF3) are assigned one CGR array each.

In all the examples above, some CGR arrays of the reconfigurable processor 810 may be unused, if desired. As an example, the reconfigurable processor 810 may have four CGR arrays out of which one CGR array is controlled by a virtual function, whereas one, two, or three of the remaining CGR arrays are unused. As another example, a virtual function may be assigned two adjacent CGR arrays and the two other CGR arrays are unused.

Illustratively, the physical CGR array or physical CGR arrays of the reconfigurable processor 810 that execute a virtual function may be abstracted from the user. In the scenario in which the reconfigurable processor 810 has four physical CGR arrays that are denoted CGR array 0, CGR array 1, CGR array 2, and CGR array 3, and the virtual function is executing on a single physical CGR array, the virtual function may execute on any one of the CGR arrays. However, the virtual function may appear to always execute on CGR array 0 of the reconfigurable processor, if desired. In other words, the reconfigurable processor 810 may dynamically map the references of the virtual function onto the physical CGR array.

It should be noted that the reconfigurable processor is described with four CGR arrays for illustration purposes only. However, one skilled in the art would appreciate that the described technology equally applies to other reconfigurable processors with a different number of CGR arrays. For example, the reconfigurable processor may have five, six, seven, or more CGR arrays. If desired, the reconfigurable processor may have a single CGR array (i.e., no distinction into separate CGR arrays), two CGR arrays, or three CGR arrays. Furthermore, the CGR arrays may be arranged in any configuration. As an example, the CGR arrays may be arranged in a column or in a row. As another example, the CGR arrays may be arranged in an M×N array. If desired, at least two reconfigurable processors may be grouped together (e.g., on a same printed circuit board (PCB), in a same rack, etc.).

By way of example, a reconfigurable processor such as CGR processor 110 of FIG. 1 may have a PCIe interface that connects the reconfigurable processor to a runtime processor such as runtime processor 180 of FIG. 1 through a PCIe switch.

Illustratively, the runtime processor may use a certain address range for the physical address and other, different address ranges for each virtual function (VF). Thus, the address may define the referenced physical function (PF) or virtual function (e.g., VF1, VF2, VF3, or VF4) based on the address range with which the address is associated. Illustratively, the addresses for the physical and/or virtual functions may be tracked as part of the PCIe device configuration. If desired, the PCIe core may use an Advanced eXtensible Interface (AXI) with a function identifier that identifies the corresponding physical or virtual function to interface with the other portions of the reconfigurable processor.

FIG. 9 is a diagram of illustrative virtualization mailboxes between a physical function 910 and virtual functions 920, 930.

Illustratively, there may be twice as many virtualization mailboxes as the number of virtual functions supported by the reconfigurable processor. For example, there may be one virtualization mailbox from the physical function 910 to each virtual function 920, 930 and one virtualization mailbox from each virtual function 920, 930 to the physical function 910. As shown in FIG. 9 , there are two virtualization mailboxes 942, 944 between PF 910 and VF1 920, a first virtualization mailbox 942 from PF 910 to VF1 920 and a second virtualization mailbox 944 from VF1 920 to PF 910, and there are two virtualization mailboxes 946, 948 between PF 910 and VF2 930, a third virtualization mailbox 946 from PF 910 to VF2 930 and a fourth virtualization mailbox 948 from VF2 930 to PF 910.

Each virtualization mailbox pair (between PF and each VF) may include a predetermined number of control registers and/or mailbox message buffers. If desired, each virtualization mailbox of a virtualization mailbox pair may include a mailbox message buffer and a control register. The control register may be adapted for signaling when a mailbox message buffer has received a message and when the message has been retrieved from the mailbox message buffer, thereby facilitating mailbox message buffer management handshake between the PF and the VF as they allow PF and VF to signal when a mailbox message buffer is free for reuse. As shown in FIG. 9 , each virtualization mailbox of virtualization mailbox pair 942, 944 may include a control registers 952, 954 and a mailbox message buffer 951, 953.

If desired, PF 910 may generate an interrupt when PF 910 sends a message to VF1, and the reconfigurable processor may be adapted for only notifying VF1 driver about the interrupt, which in turn may notify VF1 that a message has been delivered.

In some implementations, a reconfigurable processor (e.g., CGR processor 110 of FIG. 1 ) includes a PCIe interface (e.g., I/O interface 138 of FIG. 1 ) that couples the reconfigurable processor to a runtime processor (e.g., runtime processor 180 of FIG. 1 ) through a PCIe bus (e.g., communication link 185 of FIG. 1 may be a PCIe bus). In these implementations, the runtime processor may be adapted for configuring the PCIe interface as a single-root input-output virtualization (SR-IOV) interface. The SR-IOV interface may allow a reconfigurable processor to separate access to its resources among various PCIe hardware functions.

For example, the SR-IOV interface may provide access to one or more CGR arrays (e.g., CGR arrays 120) on the reconfigurable processor through the PCIe bus from a physical function driver (e.g., PF driver 183 of FIG. 1 ) and from at least one virtual function driver (e.g., VF1 driver 186 and/or VF2 driver 187 of FIG. 1 ).

Resources of the reconfigurable processor such as control and status registers (CSRs), compute units, memory units, and an array-level network, may be divided between a physical function that is associated with the physical function driver and virtual functions that are associated with the virtual function drivers. Some resources may be exclusively controlled by the physical function, and the virtual function may have no access to these resources. As an example, the physical function may include controls for enabling virtual functions and the virtual functions may have no access to these controls.

In some implementations, the physical function (PF) is a PCIe function of a network adapter (e.g., an I/O resource on a PCIe interface) that supports the single root I/O virtualization (SR-IOV) interface, as defined by the PCI Special Interest Group (PCISIG) “Single Root I/O Virtualization and Sharing Specification, Rev. 1.0”, which is incorporated by reference herein, and as updated through various engineering change notices (ECNs) and specification updates. Physical functions may be fully featured PCIe functions that can be discovered, managed, and manipulated like any other PCIe device. The PF may be used to configure and control the SR-IOV functionality of the network adapter, such as enabling virtualization and exposing PCIe Virtual Functions (VFs). A virtual function (VF) may be a PCIe function that has one or more physical resources in common with the physical function and with virtual functions that are associated with that physical function. A VF can only configure its own behavior.

Illustratively, a runtime processor may configure the devices (e.g., reconfigurable processors, storage devices, etc.) on a PCIe bus. For example, the runtime processor may query the devices on the PCIe bus to determine the amount of memory space and the supported functions of the devices. If desired, the runtime processor may enable or disable virtual functions.

When a virtual function is enabled, a predetermined number of base address registers (BARs) of a PCIe interface may be programmed for the virtual function. FIG. 10 is a diagram of an illustrative programming of base address registers (BARs) for virtual functions that are assigned arrays of CGR units in a CGR processor 1020.

Illustratively, runtime processor 1080 may include physical function driver 1085 and virtual function drivers 1086, 1087. Physical function driver 1085 may communicate via the PCIe bus with PF 1095, VF1 driver 1086 may communicate via the PCIe bus with VF1 1096, and VF2 driver 1087 may communicate via the PCIe bus with VF2 1097.

By way of example, runtime processor 1080 may be adapted for programming two BARs in the PCIe interface of the CGR processor 1020 that are associated with a configuration space, two BARs that are associated with memory access operations, and two BARs that are associated with accessing control and status registers, to implement the virtual functions VF1 1096 and VF2 1097 on the CGR processor 1020.

For example, BAR 0/1 may be associated with a configuration space (e.g., for PCIe controller configuration), BAR 2/3 with memory access operations (e.g., DRAM and/or other device memory), and BAR 4/5 may be used for accessing configuration and status registers (CSRs) and/or other resources within the arrays of CGR units. If desired, the BARs that are associated with the virtual functions VF1 1096 and VF2 1097 may be associated with corresponding virtual function drivers VF1 driver 1086 and VF2 driver 1087 within the runtime processor, respectively.

Thus, the virtual functions VF1 1096 and VF2 1097 are assigned three address ranges, whereby each virtual function of virtual functions VF1 1096 and VF2 1097 is assigned its own set of three address ranges, and the physical function 1095 is assigned three address ranges. The elements of the CGR processor 1020 that are accessible through the three address ranges may differ. For example, some registers may be reserved for the physical function 1095.

By way of example, the reconfigurable processor may provide BAR 2/3 as one virtualization feature. The software that configures the reconfigurable processor and enables the VFs may configure BAR 2/3 for each VF of the VFs to determine the amount of physical memory that the VF can access. If desired, the interface between the PCIe bus and the reconfigurable processor may include a Real to Physical Buffer (R2PB). The R2PB may provide for memory protection and memory address translation. For example, the software configuring the reconfigurable processor may program the R2PB to translate the addresses used by each VF in its BAR 2/3 address range into physical addresses for the device memory. The R2PB may provide the configuring software the ability to map each VF's memory accesses to different physical addresses, or to map some or all address ranges to shared physical addresses.

Illustratively, the reconfigurable processor may check BAR 4/5 accesses for virtual functions and ensure that the access is for a supported address. If desired, the reconfigurable processor may report virtual function accesses to CSRs that are reserved for the physical function as errors.

As mentioned above, the reconfigurable processor (e.g., CGR processor 110 of FIG. 1 ) may be adapted for generating an interrupt to the runtime processor (e.g., runtime processor 180 of FIG. 1 ) in response to a predetermined event. The predetermined event may include at least one of a load-complete event, an execution-complete event, a checkpoint event, a direct memory access (DMA) completion event, a DMA error event, a memory access error, a runtime exception (e.g., a numerical exception occurring in a compute unit or an address-out-of-bounds exception occurring in a memory unit), or interrupts from other sources (e.g., performance interrupts or program completion interrupts).

FIG. 11 is a diagram of an illustrative system with a reconfigurable processor 1110 and a runtime processor 1180 that are coupled by a PCIe bus 1165. The reconfigurable processor 1110 includes arrays of CGR units 1120, which are herein also referred to as CGR arrays 1120.

As shown in FIG. 11 , the runtime processor 1180 may provide access to the arrays of CGR units 1120 through the PCIe bus 1165 from a physical function driver 1185 and from two virtual functions drivers 1186, 1187. The physical function 1195 that is associated with the physical function driver 1185 has exclusive access to a first portion of the arrays of CGR units, and the physical function 1195 shares access to a second portion of the arrays of CGR units with the two virtual functions 1196, 1197 that are associated with the virtual function drivers 1186, 1187, respectively, whereby the first and second portions of the arrays of CGR units are different.

In some implementations, the reconfigurable processor 1110 may be adapted for generating an interrupt 1140 in response to a predetermined event. For example, the predetermined event may include at least one of a load-complete event, an execution-complete event, a checkpoint event, a direct memory access (DMA) completion event, a DMA error event, a memory access error, or a runtime exception.

The reconfigurable processor 1110 may configure delivery of the interrupt 1140 for physical function driver 1185 and virtual function drivers 1186, 1187. The reconfigurable processor 1110 may route the interrupt 1140 to the appropriate physical function driver 1185 and/or virtual function drivers 1186, 1187 based on the event generating the interrupt 1140, the portion of the reconfigurable processor 1110 detecting or reporting the event, and the configuration of the virtual functions 1196, 1197 (e.g., the number of enabled VFs and their binding to the portions of the reconfigurable processor 1110).

As an example, VF1 1196 may have exclusive access among virtual functions VF1 1196 and VF2 1197 to a predetermined array (of the arrays of CGR units 1120. In this example, the reconfigurable processor 1110 is adapted for only routing the interrupt 1140 to the physical function driver 1185 and to VF1 driver 1186 when the predetermined event occurred in the predetermined array of the arrays of CGR units 1120.

As another example, external memory (e.g., memory 190 of FIG. 1 ) may be operatively coupled to the PCIe bus 1165 and VF1 1196 may have exclusive access among virtual functions VF1 1196 and VF2 1197 to a predetermined portion of the external memory. In this example, the reconfigurable processor 1110 is adapted for only routing the interrupt 1140 to the physical function driver 1185 and to VF1 driver 1186 when the predetermined event occurred in the predetermined portion of the external memory or during access to the predetermined portion of the external memory.

As yet another example, reconfigurable processor 1110 may include a virtualization mailbox for sending messages from physical function 1195 to virtual function 1196. If desired, the physical function 1195 may generate an additional interrupt when PF 1195 sends a message to VF1 1196. In this example, the reconfigurable processor 1110 is adapted for only routing the additional interrupt to VF1 1196.

In some implementations, the reconfigurable processor 1110 may include storage circuitry. The storage circuitry may be adapted for storing a first identifier that identifies an array of the arrays of CGR units 1120 that generated the interrupt 1140 and for storing a second identifier that identifies the predetermined event that caused the interrupt.

Illustratively, the reconfigurable processor 1110 is adapted for implementing a PCIe message signaled interrupt (MSI-X) 1150 in response to the predetermined event. The message signaled interrupt (MSI-X) may record interrupts in the storage circuitry. For example, the storage circuitry may include status registers 1152 and an interrupt status array (ISA) 1154. Status registers 1152 and ISA 1154 may have one entry for each interrupt.

The status registers 1152 may be adapted for storing the first identifier that identifies an array of the arrays of CGR units 1120 that generated the interrupt, and the ISA may be adapted for storing the second identifier that identifies the predetermined event that caused the interrupt. In some implementations, the ISA may store both the first and second identifiers. Illustratively, the runtime processor 1180 may be adapted for implementing a pair of interrupt status array status registers for the physical function driver 1185 and another pair of interrupt status array status register for each virtual function driver 1186, 1187. As shown in FIG. 11 , the runtime processor 1180 may implement status registers 1142 and ISA 1144 for the physical function driver 1185, status registers 1132 and ISA 1134 for virtual function driver 1186, and status registers 1122 and ISA 1124 for virtual function driver 1187.

In some implementations, the status registers are the CSRs of the PCIe interface and are fully virtualized. Thus, each virtual function driver 1186, 1187 may access its own status registers 1132, 1122 using the same addresses. The ISA (and the controls for the MSI-X messages) may be part of the MSI-X address region.

MSI-X interrupts 1150 generated from the PCIe host end point (HEP) may be disabled individually or all together using the MSI-X configuration registers in the PCIe configuration space. If desired, all interrupt events may be disabled in their respective source agent CSRs. Both MSI-X config and the source agent CSRs may be configured for an MSI-X interrupt to be sent.

Each interrupt request may be assigned an interrupt number. An interface may translate an event reported from any agent to an Interrupt Vector Number (INT #) along with an optional Event Data bit that can further specify one of the two possible events. Interrupt requests that are mutually exclusive (e.g., the AGCU program load and program execute completion, program checkpoint complete and program quiesce complete, or host tail pointer update and host header pointer update, just to name a few) may be merged into a single interrupt using this scheme. If desired, this scheme may be extended beyond two events in the group of mutually exclusive events being reported using a same Interrupt Vector Number (INT #), if desired.

Events and interrupts may be available to the PF driver 1185, e.g., the PF driver 1185 can subscribe to events and interrupts regardless of the virtualization status.

The CGR array-specific events, the DMA events, real to physical buffer (R2PB) misses, and the virtualization mailbox interrupt may be available to the VF drivers 1186, 1187 when virtualization is enabled. If multiple CGR arrays are assigned to one VF (e.g., as shown in FIGS. 8B, 8C, and 8D), then the events from different CGR arrays may be reported using separate and incremental interrupt numbers, if desired.

As an example, a virtualization mailbox from a VF to the PF (e.g., virtualization mailbox 944 or 948 of FIG. 9 ) may generate an interrupt to the PF driver when the VF puts something in the virtualization mailbox, and the PF driver may receive this interrupt and notify the PF that something is in the virtualization mailbox. As another example, a virtualization mailbox from the PF to a VF (e.g., virtualization mailbox 942 or 946 of FIG. 9 ) may generate an interrupt to the VF driver when the PF puts something in the mailbox, and the VF driver may receive this interrupt and notify the VF that something is in the virtualization mailbox.

Illustratively, the reconfigurable processor 1110 may provide for N different interrupt identifiers that are numbered from 1 to N. The interrupt identifiers could alternatively be numbered from 0 to N−1, if desired. As an example, the reconfigurable processor may provide for N=32 interrupt numbers. It should be noted that the reconfigurable processor may provide a different number of interrupt numbers. For example, the reconfigurable processor may provide more or less than 32 number of interrupts.

Consider the scenario in which the reconfigurable processor 1110 supports 32 interrupts that are numbered 0 to 31. Consider further that the reconfigurable processor 1110 supports 26 virtualized interrupts.

The virtualized interrupts (e.g., interrupts 1 to 26 of interrupts 0 to 31) have to be mapped for PF and VF. Illustratively, the interrupts map directly for PF. In other words, PF may receive the interrupts as physical interrupt numbers. For several interrupt groups, a single event identifier may generate one of several physical interrupt numbers. The AGCU that sent the request may determine which physical interrupt is generated. For example, in the scenario in which the reconfigurable processor includes four CGR arrays, physical interrupt 3 may be generated in response to the master AGCU on physical CGR array 3 sending event ID 0. Thus, AGCU Event IDs 0 and 1 may generate physical interrupts 1 to 4, AGCU Event IDs 2 and 4 may generate physical interrupts 5 to 8, AGCU Event IDs 5 and 6 may generate physical interrupts 19 to 22, and AGCU Event ID 3 may generate physical interrupts 23 to 26.

TABLE 1 Mapping between physical interrupt numbers and actual interrupt numbers Physical PF 2H VF 2V VF 1 VF Number Number 4 VF Mappings Mappings Mappings Mappings Interrupt Interrupt VF1 VF2 VF3 VF4 VF1 VF2 VF1 VF2 VF1 1 1 1 1 1 1 2 2 1 2 1 2 3 3 1 1 2 3 4 4 1 2 2 4 5 5 5 5 5 5 6 6 5 6 5 6 7 7 5 5 6 7 8 8 5 6 6 8 11 11 11 11 11 11 12 12 12 12 12 12 13 13 11 13 13 13 14 14 12 14 14 14 15 15 11 11 11 15 16 16 12 12 12 16 17 17 11 13 13 17 18 18 12 14 14 18 19 19 19 19 19 19 20 20 19 20 19 20 21 21 19 19 20 21 22 22 19 20 20 22 23 23 23 23 23 23 24 24 23 24 23 24 25 25 23 23 24 25 26 26 23 24 24 26

Table 1 shows an illustrative mapping between physical interrupt numbers and actual interrupt numbers for the virtual functions for a reconfigurable processor having four CGR arrays with four virtual functions enabled (4VF Mappings) as shown in FIG. 8D, two virtual functions enabled (2H VF Mappings) as shown in FIG. 8C, two virtual functions enabled (2V VF Mappings) as shown in FIG. 8B, and one virtual function enabled (1VF Mappings) as shown in FIG. 8A.

For example, physical interrupt numbers 1 to 4 may indicate an event of a first predetermined type that occurred in the respective CGR arrays 1 to 4. In this example, the physical function and/or the associated physical function driver and the one virtual function that is assigned all four CGR arrays (VF1 Mapping) and/or the associated virtual function driver may receive the interrupt numbers 1 to 4. Each one of the four enabled virtual functions VF1 to VF4 (VF4 Mappings) and/or the associated virtual function driver may receive the interrupt number 1 to indicate that the first predetermined event has occurred in the CGR array in which the virtual function is enabled. In the 2H VF Mappings, VF1 is assigned CGR arrays 1 and 2, and VF2 is assigned CGR arrays 3 and 4. Therefore, VF1 and/or the associated virtual function driver receives interrupt numbers 1 and 2 when the first predetermined event occurred in CGR arrays 1 and 2, respectively, and VF2 and/or the associated virtual function driver receives interrupt numbers 1 and 2 when the first predetermined event occurred in CGR arrays 3 and 4, respectively. In the 2V VF Mappings, VF1 is assigned CGR arrays 1 and 3, and VF2 is assigned CGR arrays 2 and 4. Therefore, VF1 and/or the associated virtual function driver receives interrupt numbers 1 and 2 when the first predetermined event occurred in CGR arrays 1 and 3, respectively, and VF2 and/or the associated virtual function driver receives interrupt numbers 1 and 2 when the first predetermined event occurred in CGR arrays 2 and 4, respectively.

If desired, some CSRs may allow the physical function to disable the reporting of specific events from specific units to the virtual functions, and other CSRs may allow the virtual functions to disable reporting of specific events from specific units to itself. Because these disables affect interrupt delivery to VFs, interrupt requests that do not generate virtualized interrupts do not need these controls. For example, DDR and HBM may have no interrupt requests that generate interrupts to VFs and so have no virtualization interrupt request disables.

FIG. 12 is a flowchart 1200 showing illustrative operations that a runtime processor may perform in a system (e.g., system 100 of FIG. 1 ) such that virtual functions are enabled. An example system as shown in FIG. 1 includes a communication link 185, a runtime processor 180 that is operatively coupled to the communication link 185, and a reconfigurable processor 110 that includes at least one array of coarse-grained reconfigurable units 120 and an interface 138 operatively coupled to the communication link 185 thereby coupling the reconfigurable processor 110 to the runtime processor 180 via the communication link 185.

During operation 1210, the runtime processor configures the interface to the communication link to provide access to the at least one array of coarse-grained reconfigurable units through the communication link from a physical function driver. For example, the runtime processor 180 of FIG. 1 may configure the interface 138 to the communication link 185 to provide access to the at least one array of coarse-grained reconfigurable units 120 through the communication link 185 from a physical function driver 183.

During operation 1220, the runtime processor configures a physical function on the reconfigurable processor that is associated with the physical function driver, wherein the physical function is provided access to both a first portion and a second portion of the at least one array of coarse-grained reconfigurable units. For example, the runtime processor 180 of FIG. 1 may configure the physical function 195 on the reconfigurable processor 110 that is associated with the physical function driver 183, whereby the physical function 195 is provided access to both a first and a second portion of the at least one array of coarse-grained reconfigurable units 120.

During operation 1230, the runtime processor configures the interface to the communication link to provide access to the at least one array of coarse-grained reconfigurable units through the communication link from at least one virtual function driver. For example, the runtime processor 180 of FIG. 1 may provide access to the at least one array of coarse-grained reconfigurable units 120 through the communication link 138 from at least one virtual function driver 186.

During operation 1240, the runtime processor configures at least one virtual function on the reconfigurable processor that is associated with the at least one virtual function driver, wherein the at least one virtual function is provided access to the second portion of the at least one array of coarse-grained reconfigurable units and is blocked from accessing the first portion of the at least one array of coarse-grained reconfigurable units.

For example, the runtime processor 180 of FIG. 1 may configure at least one virtual function 196 that is associated with the at least one virtual function driver 186 on the reconfigurable processor 110, whereby the at least one virtual function 196 is provided partial access to the at least one array of coarse-grained reconfigurable units 120.

In some implementations, the reconfigurable processor comprises four arrays (e.g., CGR arrays 211, 212, 213, 214 of reconfigurable processor 200 of FIG. 2 ). In these implementations, the runtime processor may configure the interface to the communication link to one of a first configuration wherein up to four virtual functions of the at least one virtual function are enabled, each assigned a separate array of the four arrays of coarse-grained reconfigurable units, a second configuration wherein up to two virtual functions of the at least one virtual function are enabled, each assigned two adjacent arrays of the four arrays of coarse-grained reconfigurable units, and a third configuration wherein a single virtual function of the at least one virtual function is assigned the four arrays of coarse-grained reconfigurable units.

For example, the runtime processor 180 of FIG. 1 may configure the interface 138 to the communication link 185 to one of a first configuration wherein up to four virtual functions of the at least one virtual function are enabled, each assigned a separate array of the four arrays of coarse-grained reconfigurable units (e.g., as shown in FIG. 8A), a second configuration wherein up to two virtual functions of the at least one virtual function are enabled, each assigned two adjacent arrays of the four arrays of coarse-grained reconfigurable units (e.g., as shown in FIG. 8B or FIG. 8C), and a third configuration wherein a single virtual function of the at least one virtual function is assigned the four arrays of coarse-grained reconfigurable units (e.g., as shown in FIG. 8D).

In some scenarios, the communication link comprises a Peripheral Component Interface Express (PCIe) bus and the interface to the communication link comprises a PCIe interface. In these scenarios, the runtime processor may program a predetermined number of base address registers (BARs) of the PCIe interface for a virtual function of the at least one virtual function.

In some implementations, when programming a predetermined number of BARs of the PCIe interface for the virtual function of the at least one virtual function, the runtime processor may program for the virtual function of the at least one virtual function two BARs that are associated with a configuration space, two BARs that are associated with memory access operations, and two BARs that are associated with accessing control and status registers. If desired, the BARs that are associated with the virtual function of the at least one virtual function may be assigned to a corresponding virtual function driver within the runtime processor.

In the scenario above in which the communication link comprises a Peripheral Component Interface Express (PCIe) bus and the interface to the communication link is a PCIe interface, the runtime processor may configure the PCIe interface as a single-root input-output virtualization (SR-IOV) interface to provide access to the at least one array of coarse-grained reconfigurable units through the PCIe bus from the physical function driver and from the at least one virtual function driver.

If desired, a non-transitory computer-readable storage medium includes instructions that, when executed by a processing unit (e.g., runtime processor 180 of FIG. 1 ), cause the processing unit to operate a system (e.g., system 100 of FIG. 1 ) by performing operations 1210 to 1240.

For example, such a non-transitory computer-readable storage medium may include instructions for configuring the interface to the communication link to provide access to the at least one array of coarse-grained reconfigurable units through the communication link from a physical function driver; configuring a physical function on the reconfigurable processor that is associated with the physical function driver, wherein the physical function is provided access to both a first portion and a second portion of the at least one array of coarse-grained reconfigurable units; configuring the interface to the communication link to provide access to the at least one array of coarse-grained reconfigurable units through the communication link from at least one virtual function driver; and configuring at least one virtual function on the reconfigurable processor that is associated with the at least one virtual function driver, wherein the at least one virtual function is provided access to the second portion of the at least one array of coarse-grained reconfigurable units and is blocked from accessing the first portion of the at least one array of coarse-grained reconfigurable units.

FIG. 13 is a flowchart 1300 showing illustrative operations that a runtime processor may perform in a system (e.g., system 100 of FIG. 1 ) for handling interrupts when virtual functions are enabled in a reconfigurable processor. An example system as shown in FIG. 1 includes a communication link 185, a runtime processor 180 that is operatively coupled to the communication link 185, and a reconfigurable processor 110 that includes multiple arrays of coarse-grained reconfigurable units 120 and an interface 138 to the communication link 185 that couples the reconfigurable processor 110 to the runtime processor 180 via the communication link 185.

During operation 1310, the runtime processor configures the interface to the communication link to provide access to the multiple arrays of coarse-grained reconfigurable units from a physical function driver and from at least one virtual function driver.

For example, the runtime processor 180 of FIG. 1 may configure the interface 138 to the communication link 185 to provide access to the multiple arrays of coarse-grained reconfigurable units 120 from a physical function driver 183 and from at least one virtual function driver 186, 187.

During operation 1320, the reconfigurable processor generates an interrupt in response to a predetermined event. For example, the reconfigurable processor 110 of FIG. 1 may generate interrupt 181 in response to an event in one of the CGR arrays 120 that is assigned to virtual function VF1 196.

During operation 1330, the reconfigurable processor reports the interrupt to the physical function driver in the runtime processor and to a virtual function driver of the at least one virtual function driver in the runtime processor. As an example, the reconfigurable processor 110 of FIG. 1 may report the interrupt 181 to the physical function driver 183 of runtime processor 180 and to VF1 driver 186 of runtime processor 180. As another example, the reconfigurable processor 110 of FIG. 1 may report the interrupt 181 to the physical function driver 183 of runtime processor 180 and to VF2 driver 187 of runtime processor 180.

In some implementations, the reconfigurable processor further comprises storage circuitry for storing a first identifier in the storage circuitry that identifies an array of the multiple arrays of coarse-grained reconfigurable units that generated the interrupt and for storing a second identifier in the storage circuitry that identifies the predetermined event that caused the interrupt.

Illustratively, the communication link comprises a Peripheral Component Interface Express (PCIe) bus, and the reconfigurable processor may implement a PCIe message signaled interrupt (MSI-X) in response to the predetermined event.

By way of example, a first virtual function of the at least one virtual function, that is associated with a first virtual function driver of the at least one virtual function driver, has exclusive access among the at least one virtual function to a predetermined array of the multiple arrays of coarse-grained reconfigurable units, and the reconfigurable processor only notifies the physical function driver and the first virtual function driver about the interrupt when the predetermined event occurred in the predetermined array of the multiple arrays of coarse-grained reconfigurable units.

In some implementations, the system may include external memory (e.g., memory 190 of system 100 of FIG. 1 ) that is operatively coupled to the communication link, and a first virtual function of the at least one virtual function that is associated with a first virtual function driver of the at least one virtual function driver has exclusive access among the at least one virtual function to a predetermined portion of the external memory. In these implementations, the reconfigurable processor may only notify the physical function driver and the first virtual function driver about the interrupt when the predetermined event occurred in the predetermined portion of the external memory or during access to the predetermined portion of the external memory.

In some implementations, the reconfigurable processor includes a virtualization mailbox for sending messages from the physical function to a first virtual function of the at least one virtual function, and the physical function may generate an additional interrupt when the physical function sends a message to the first virtual function. In these implementations, the reconfigurable processor may only notify the first virtual function about the additional interrupt.

If desired, a non-transitory computer-readable storage medium includes instructions that, when executed by a processing unit (e.g., runtime processor 180 of FIG. 1 ), cause the processing unit to operate a system (e.g., system 100 of FIG. 1 ) by performing operations 1310, 1320, and 1330.

For example, a non-transitory computer-readable storage medium includes instructions for configuring the interface to the communication link to provide access to the multiple arrays of coarse-grained reconfigurable units from a physical function driver and from at least one virtual function driver, for generating an interrupt in response to a predetermined event, and for reporting the interrupt to the physical function driver in the runtime processor and to a virtual function driver of the at least one virtual function driver in the runtime processor.

While the present invention is disclosed by reference to the preferred embodiments and examples detailed above, it is to be understood that these examples are intended in an illustrative rather than in a limiting sense. It is contemplated that modifications and combinations will readily occur to those skilled in the art, which modifications and combinations will be within the spirit of the invention and the scope of the following claims.

As will be appreciated by those of ordinary skill in the art, aspects of the presented technology may be embodied as a system, device, method, or computer program product apparatus. Accordingly, elements of the present disclosure may be implemented entirely in hardware, entirely in software (including firmware, resident software, micro-code, or the like) or in software and hardware that may all generally be referred to herein as a “apparatus,” “circuit,” “circuitry,” “module,” “computer,” “logic,” “FPGA,” “unit,” “system,” or other terms. Furthermore, aspects of the presented technology may take the form of a computer program product embodied in one or more computer-readable medium(s) having computer program code stored thereon. The phrases “computer program code” and “instructions” both explicitly include configuration information for a CGRA, an FPGA, or other programmable logic as well as traditional binary computer instructions, and the term “processor” explicitly includes logic in a CGRA, an FPGA, or other programmable logic configured by the configuration information in addition to a traditional processing core. Furthermore, “executed” instructions explicitly includes electronic circuitry of a CGRA, an FPGA, or other programmable logic performing the functions for which they are configured by configuration information loaded from a storage medium as well as serial or parallel execution of instructions by a traditional processing core.

Any combination of one or more computer-readable storage medium(s) may be utilized. A computer-readable storage medium may be embodied as, for example, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or other like storage devices known to those of ordinary skill in the art, or any suitable combination of computer-readable storage mediums described herein. In the context of this document, a computer-readable storage medium may be any tangible medium that can contain, or store, a program and/or data for use by or in connection with an instruction execution system, apparatus, or device. Even if the data in the computer-readable storage medium requires action to maintain the storage of data, such as in a traditional semiconductor-based dynamic random-access memory, the data storage in a computer-readable storage medium can be considered to be non-transitory. A computer data transmission medium, such as a transmission line, a coaxial cable, a radio-frequency carrier, and the like, may also be able to store data, although any data storage in a data transmission medium can be said to be transitory storage. Nonetheless, a computer-readable storage medium, as the term is used herein, does not include a computer data transmission medium.

Computer program code for carrying out operations for aspects of the present technology may be written in any combination of one or more programming languages, including object-oriented programming languages such as Java, Python, C++, or the like, conventional procedural programming languages, such as the “C” programming language or similar programming languages, or low-level computer languages, such as assembly language or microcode. In addition, the computer program code may be written in VHDL, Verilog, or another hardware description language to generate configuration instructions for an FPGA, CGRA IC, or other programmable logic. The computer program code if converted into an executable form and loaded onto a computer, FPGA, CGRA IC, or other programmable apparatus, produces a computer implemented method. The instructions which execute on the computer, FPGA, CGRA IC, or other programmable apparatus may provide the mechanism for implementing some or all of the functions/acts specified in the flowchart and/or block diagram block or blocks. In accordance with various implementations, the computer program code may execute entirely on the user's device, partly on the user's device and partly on a remote device, or entirely on the remote device, such as a cloud-based server. In the latter scenario, the remote device may be connected to the user's device through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). The computer program code stored in/on (i.e. embodied therewith) the non-transitory computer-readable medium produces an article of manufacture.

The computer program code, if executed by a processor, causes physical changes in the electronic devices of the processor which change the physical flow of electrons through the devices. This alters the connections between devices which changes the functionality of the circuit. For example, if two transistors in a processor are wired to perform a multiplexing operation under control of the computer program code, if a first computer instruction is executed, electrons from a first source flow through the first transistor to a destination, but if a different computer instruction is executed, electrons from the first source are blocked from reaching the destination, but electrons from a second source are allowed to flow through the second transistor to the destination. So, a processor programmed to perform a task is transformed from what the processor was before being programmed to perform that task, much like a physical plumbing system with different valves can be controlled to change the physical flow of a fluid.

Example 1 is a data processing system, comprising: a communication link; a runtime processor that is operatively coupled to the communication link; and one or more reconfigurable processors. A reconfigurable processor of the one or more reconfigurable processors comprises at least one array of coarse-grained reconfigurable units; and an interface to the communication link that is operatively coupled to the communication link, thereby coupling the reconfigurable processor to the runtime processor via the communication link, wherein the runtime processor is adapted for configuring the interface to the communication link to provide access to the at least one array of coarse-grained reconfigurable units through the communication link from a physical function driver and from at least one virtual function driver, wherein the physical function that is associated with the physical function driver has exclusive access to a first portion of the at least one array of coarse-grained reconfigurable units, and wherein the physical function shares access to a second portion of the at least one array of coarse-grained reconfigurable units that is different than the first portion with at least one virtual function that is associated with the at least one virtual function driver.

In Example 2, the reconfigurable processor of the one or more reconfigurable processors of Example 1 may optionally include N arrays of coarse-grained reconfigurable units, where N is an integer greater than 1.

In Example 3, the runtime processor of Example 2 may optionally be adapted for configuring the interface to the communication link to provide access to the N arrays of coarse-grained reconfigurable units to the physical function and to up to N virtual functions.

In Example 4, each virtual function of the up to N virtual functions of Example 3 may optionally have exclusive access among the up to N virtual functions to at least one of the N arrays of coarse-grained reconfigurable units.

In Example 5, N equals 4 and the runtime processor of Example 3 may optionally be adapted for configuring the interface to the communication link, based at least in part on a number of virtual functions to enable of the at least one virtual function and resource requirements of the at least one virtual function, to one of: a first configuration wherein up to four virtual functions of the at least one virtual function are enabled, each assigned a separate array of the four arrays of coarse-grained reconfigurable units, a second configuration wherein up to two virtual functions of the at least one virtual function are enabled, each assigned two adjacent arrays of the four arrays of coarse-grained reconfigurable units, and a third configuration wherein a single virtual function of the at least one virtual function is assigned the four arrays of coarse-grained reconfigurable units.

In Example 6, the data processing system of Example 1 may optionally include a first virtualization mailbox for sending messages from the physical function to a first virtual function of the at least one virtual function; and a second virtualization mailbox for sending messages from the first virtual function to the physical function.

In Example 7, each one of the first and second virtualization mailboxes of Example 6 may optionally include: a mailbox message buffer; and a control register that is adapted for signaling when a mailbox message buffer has received a message and when the message has been retrieved from the mailbox message buffer.

In Example 8, the runtime processor of Example 1 may optionally be adapted for programming a predetermined number of base address registers (BARs) of the interface to the communication link for a virtual function of the at least one virtual function, wherein the communication link comprises a Peripheral Component Interface Express (PCIe) bus.

In Example 9, the runtime processor of Example 8 may optionally be adapted for programming for the virtual function of the at least one virtual function two BARs that are associated with a configuration space, two BARs that are associated with memory access operations, and two BARs that are associated with accessing control and status registers.

In Example 10, the interface to the communication link is a PCIe interface, and the runtime processor of Example 8 may optionally be adapted for configuring the PCIe interface as a single-root input-output virtualization (SR-IOV) interface to provide access to the at least one array of coarse-grained reconfigurable units through the PCIe bus from the physical function and from the at least one virtual function.

In Example 11, the reconfigurable processor of Example 1 may optionally be adapted for generating an interrupt to the runtime processor in response to a predetermined event.

In Example 12, the predetermined event of Example 11 may optionally include at least one of a load-complete event, an execution-complete event, a checkpoint event, a direct memory access (DMA) completion event, a DMA error event, a memory access error, or a runtime exception.

In Example 13, wherein the communication link includes a Peripheral Component Interface Express (PCIe) bus, and the reconfigurable processor of Example 11 may optionally be adapted for implementing a PCIe message signaled interrupt (MSI-X) in response to the predetermined event.

In Example 14, the reconfigurable processor of Example 13 may optionally include status registers that are adapted for identifying an array of the at least one array of coarse-grained reconfigurable units that generated the interrupt; and an interrupt status array (ISA) that is adapted for identifying the predetermined event that caused the interrupt.

In Example 15, the reconfigurable processor of Example 14 may optionally be adapted for implementing a pair of interrupt status array status registers for the physical function and another pair of interrupt status array status register for each one of the at least one virtual function.

In Example 16, each array of the at least one array of coarse-grained reconfigurable units of Example 1 may optionally include control and status registers, compute units, memory units, and an array-level network that couples the control and status registers, the compute units, and the memory units.

Example 17 is a method of operating a system that comprises a communication link, a runtime processor that is operatively coupled to the communication link, and a reconfigurable processor that includes at least one array of coarse-grained reconfigurable units and an interface operatively coupled to the communication link thereby coupling the reconfigurable processor to the runtime processor via the communication link, comprising: configuring, with the runtime processor, the interface to the communication link to provide access to the at least one array of coarse-grained reconfigurable units through the communication link from a physical function driver; configuring, with the runtime processor, a physical function on the reconfigurable processor that is associated with the physical function driver, wherein the physical function is provided access to both a first portion and a second portion of the at least one array of coarse-grained reconfigurable units; configuring, with the runtime processor, the interface to the communication link to provide access to the at least one array of coarse-grained reconfigurable units through the communication link from at least one virtual function driver; and configuring, with the runtime processor, at least one virtual function on the reconfigurable processor that is associated with the at least one virtual function driver, wherein the at least one virtual function is provided access to the second portion of the at least one array of coarse-grained reconfigurable units and is blocked from accessing the first portion of the at least one array of coarse-grained reconfigurable units.

In Example 18, the reconfigurable processor comprises four arrays, and wherein configuring, with the runtime processor, the interface to the communication link of Example 17 optionally includes configuring, with the runtime processor, the interface to the communication link to one of: a first configuration wherein up to four virtual functions of the at least one virtual function are enabled, each being assigned a separate array of the four arrays of coarse-grained reconfigurable units, a second configuration wherein up to two virtual functions of the at least one virtual function are enabled, each being assigned two adjacent arrays of the four arrays of coarse-grained reconfigurable units, and a third configuration wherein a single virtual function of the at least one virtual function is assigned the four arrays of coarse-grained reconfigurable units.

In Example 19, the communication link comprises a Peripheral Component Interface Express (PCIe) bus and the interface to the communication link comprises a PCIe interface, and the method of Example 17 optionally includes: programming, with the runtime processor, a predetermined number of base address registers (BARs) of the PCIe interface for a virtual function of the at least one virtual function.

In Example 20, programming a predetermined number of BARs of the PCIe interface for the virtual function of the at least one virtual function of Example 19 may optionally include: programming, with the runtime processor, for the virtual function of the at least one virtual function two BARs that are associated with a configuration space, two BARs that are associated with memory access operations, and two BARs that are associated with accessing control and status registers.

In Example 21, the interface to the communication link is a PCIe interface, and the method of Example 17 may optionally include configuring, with the runtime processor, the PCIe interface as a single-root input-output virtualization (SR-IOV) interface to provide access to the at least one array of coarse-grained reconfigurable units through the PCIe bus from the physical function driver and from the at least one virtual function driver.

Example 22 is a non-transitory computer-readable storage medium including instructions that, when executed by a processing unit, cause the processing unit to operate a system that comprises a communication link, a runtime processor that is operatively coupled to the communication link, and a reconfigurable processor that includes at least one array of coarse-grained reconfigurable units and an interface operatively coupled to the communication link thereby coupling the reconfigurable processor to the runtime processor via the communication link, the instructions comprising: configuring the interface to the communication link to provide access to the at least one array of coarse-grained reconfigurable units through the communication link from a physical function driver; configuring, with the runtime processor, a physical function on the reconfigurable processor that is associated with the physical function driver, wherein the physical function is provided access to both a first portion and a second portion of the at least one array of coarse-grained reconfigurable units; configuring, with the runtime processor, the interface to the communication link to provide access to the at least one array of coarse-grained reconfigurable units through the communication link from at least one virtual function driver; and configuring, with the runtime processor, at least one virtual function on the reconfigurable processor that is associated with the at least one virtual function driver, wherein the at least one virtual function is provided access to the second portion of the at least one array of coarse-grained reconfigurable units and is blocked from accessing the first portion of the at least one array of coarse-grained reconfigurable units.

Example 23 is a system, comprising a communication link, a runtime processor that is operatively coupled to the communication link, and a reconfigurable processor adapted for generating an interrupt to the runtime processor in response to a predetermined event. The reconfigurable processor includes multiple arrays of coarse-grained reconfigurable units, and an interface to the communication link that couples the reconfigurable processor to the runtime processor via the communication link, wherein the runtime processor is adapted for configuring the interface to the communication link to provide access to the multiple arrays of coarse-grained reconfigurable units from a physical function driver and from at least one virtual function driver, and wherein the reconfigurable processor is adapted for sending the interrupt to the physical function driver and to a virtual function driver of the at least one virtual function driver within the runtime processor.

In Example 24, a physical function that is associated with the physical function driver of Example 23 may optionally have exclusive access to a first portion of the multiple arrays of coarse-grained reconfigurable units, and the physical function may optionally share access to a second portion of the multiple arrays of coarse-grained reconfigurable units that is different than the first portion with at least one virtual function that is associated with the at least one virtual function driver.

In Example 25, each virtual function of the at least one virtual function of Example 24 may optionally have exclusive access among the at least one virtual function to at least one array of the multiple arrays of coarse-grained reconfigurable units.

In Example 26, the predetermined event of Example 23 may optionally include at least one of a load-complete event, an execution-complete event, a checkpoint event, a direct memory access (DMA) completion event, a DMA error event, a memory access error, or a runtime exception.

In Example 27, the reconfigurable processor of Example 23 may optionally include storage circuitry that is adapted for storing a first identifier that identifies an array of the multiple arrays of coarse-grained reconfigurable units that generated the interrupt and for storing a second identifier that identifies the predetermined event that caused the interrupt.

In Example 28, the communication link comprises a Peripheral Component Interface Express (PCIe) bus and the reconfigurable processor of Example 27 may optionally be adapted for implementing a PCIe message signaled interrupt (MSI-X) in response to the predetermined event.

In Example 29, the storage circuitry of Example 28 may optionally include status registers that are adapted for storing the first identifier, and an interrupt status array (ISA) that is adapted for storing the second identifier.

In Example 30, the reconfigurable processor of Example 29 may optionally be adapted for implementing a pair of ISA and status registers for the physical function and another pair of ISA and status registers for each one of the at least one virtual function.

In Example 31, a first virtual function of the at least one virtual function of Example 23 may optionally have exclusive access among the at least one virtual function to a predetermined array of the multiple arrays of coarse-grained reconfigurable units, and the reconfigurable processor may optionally be adapted for only notifying the physical function driver and the first virtual function driver about the interrupt when the predetermined event occurred in the predetermined array of the multiple arrays of coarse-grained reconfigurable units.

In Example 32, the system of Example 23 may optionally include external memory that is that is operatively coupled to the communication link, wherein a first virtual function of the at least one virtual function has exclusive access among the at least one virtual function to a predetermined portion of the external memory, and wherein the reconfigurable processor is adapted for only notifying the physical function driver and the first virtual function driver about the interrupt when the predetermined event occurred in the predetermined portion of the external memory or during access to the predetermined portion of the external memory.

In Example 33, the reconfigurable processor of Example 23 may optionally include a virtualization mailbox for sending messages from the physical function to a first virtual function of the at least one virtual function, wherein the physical function generates an additional interrupt when the physical function sends a message to the first virtual function, and wherein the reconfigurable processor is adapted for only notifying the first virtual function about the additional interrupt.

Example 34 is a method of operating a system that comprises a communication link, a runtime processor that is operatively coupled to the communication link, and a reconfigurable processor comprising multiple arrays of coarse-grained reconfigurable units, and an interface to the communication link that couples the reconfigurable processor to the runtime processor via the communication link. The method comprises configuring, with the runtime processor, the interface to the communication link to provide access to the multiple arrays of coarse-grained reconfigurable units from a physical function driver and from at least one virtual function driver; generating, with the reconfigurable processor, an interrupt in response to a predetermined event; and reporting, with the reconfigurable processor, the interrupt to a physical function driver in the runtime processor and to a virtual function driver of the at least one virtual function driver in the runtime processor.

In Example 35, the reconfigurable processor further comprises storage circuitry, and the method of Example 34 may optionally include storing a first identifier in the storage circuitry that identifies an array of the multiple arrays of coarse-grained reconfigurable units that generated the interrupt; and storing a second identifier in the storage circuitry that identifies the predetermined event that caused the interrupt.

In Example 36, the communication link comprises a Peripheral Component Interface Express (PCIe) bus, and the method of Example 34 may optionally include, with the reconfigurable processor, implementing a PCIe message signaled interrupt (MSI-X) in response to the predetermined event.

In Example 37, a first virtual function of at least one virtual function, that is associated with the at least one virtual function driver, has exclusive access among the at least one virtual function to a predetermined array of the multiple arrays of coarse-grained reconfigurable units, and the method of Example 34 may optionally include, with the reconfigurable processor, only notifying the physical function driver and the first virtual function driver about the interrupt when the predetermined event occurred in the predetermined array of the multiple arrays of coarse-grained reconfigurable units.

In Example 38, the system further comprises external memory that is operatively coupled to the communication link, a first virtual function of the at least one virtual function has exclusive access among the at least one virtual function to a predetermined portion of the external memory, and the method of Example 34 may optionally include, with the reconfigurable processor, only notifying the physical function driver and the first virtual function driver about the interrupt when the predetermined event occurred in the predetermined portion of the external memory or during access to the predetermined portion of the external memory.

In Example 39, the reconfigurable processor further comprises a virtualization mailbox for sending messages from the physical function to a first virtual function of the at least one virtual function, the physical function generates an additional interrupt when the physical function sends a message to the first virtual function, and the method of Example 34 may optionally include, with the reconfigurable processor, only notifying the first virtual function about the additional interrupt.

Example 40 is a non-transitory computer-readable storage medium including instructions that, when executed by a processing unit, cause the processing unit to operate a system that comprises a communication link, a runtime processor that is operatively coupled to the communication link, and a reconfigurable processor comprising multiple arrays of coarse-grained reconfigurable units, and an interface to the communication link that couples the reconfigurable processor to the runtime processor via the communication link, the instructions comprising: configuring the interface to the communication link to provide access to the multiple arrays of coarse-grained reconfigurable units from a physical function driver and from at least one virtual function driver; generating an interrupt in response to a predetermined event; and reporting the interrupt to a physical function driver in the runtime processor and to a virtual function driver of the at least one virtual function driver in the runtime processor.

In Example 41, a first virtual function of the at least one virtual function that is associated with the at least one virtual function driver has exclusive access among the at least one virtual function to a predetermined array of the multiple arrays of coarse-grained reconfigurable units, and the instructions of Example 40 may optionally include only notifying the physical function driver and the first virtual function driver about the interrupt when the predetermined event occurred in the predetermined array of the multiple arrays of coarse-grained reconfigurable units.

In Example 42, the system further comprises external memory that is operatively coupled to the communication link, a first virtual function of the at least one virtual function has exclusive access among the at least one virtual function to a predetermined portion of the external memory, and the instructions of Example 40 may optionally include only notifying the physical function driver and the first virtual function driver about the interrupt when the predetermined event occurred in the predetermined portion of the external memory or during access to the predetermined portion of the external memory.

In Example 43, the reconfigurable processor further comprises a virtualization mailbox for sending messages from the physical function to a first virtual function of the at least one virtual function, the physical function generates an additional interrupt when the physical function sends a message to the first virtual function, and the instructions of Example 40 may optionally include only notifying the first virtual function about the additional interrupt. 

What is claimed is:
 1. A system, comprising: a communication link; a runtime processor that is operatively coupled to the communication link; and a reconfigurable processor adapted for generating an interrupt to the runtime processor in response to a predetermined event, the reconfigurable processor comprising: multiple arrays of coarse-grained reconfigurable units, and an interface to the communication link that couples the reconfigurable processor to the runtime processor via the communication link, wherein the runtime processor is adapted for configuring the interface to the communication link to provide access to the multiple arrays of coarse-grained reconfigurable units from a physical function driver and from at least one virtual function driver, and wherein the reconfigurable processor is adapted for sending the interrupt to the physical function driver and to a virtual function driver of the at least one virtual function driver within the runtime processor.
 2. The system of claim 1, wherein a physical function that is associated with the physical function driver has exclusive access to a first portion of the multiple arrays of coarse-grained reconfigurable units, and wherein the physical function shares access to a second portion of the multiple arrays of coarse-grained reconfigurable units that is different than the first portion with at least one virtual function that is associated with the at least one virtual function driver.
 3. The system of claim 2, wherein each virtual function of the at least one virtual function has exclusive access among the at least one virtual function to at least one array of the multiple arrays of coarse-grained reconfigurable units.
 4. The system of claim 1, wherein the predetermined event comprises at least one of a load-complete event, an execution-complete event, a checkpoint event, a direct memory access (DMA) completion event, a DMA error event, a memory access error, or a runtime exception.
 5. The system of claim 1, wherein the reconfigurable processor further comprises: storage circuitry that is adapted for storing a first identifier that identifies an array of the multiple arrays of coarse-grained reconfigurable units that generated the interrupt and for storing a second identifier that identifies the predetermined event that caused the interrupt.
 6. The system of claim 5, wherein the communication link comprises a Peripheral Component Interface Express (PCIe) bus and the reconfigurable processor is adapted for implementing a PCIe message signaled interrupt (MSI-X) in response to the predetermined event.
 7. The system of claim 6, wherein the storage circuitry further comprises: status registers that are adapted for storing the first identifier; and an interrupt status array (ISA) that is adapted for storing the second identifier.
 8. The system of claim 7, wherein the reconfigurable processor is adapted for implementing a pair of ISA and status registers for the physical function and another pair of ISA and status registers for each one of the at least one virtual function.
 9. The system of claim 1, wherein a first virtual function of the at least one virtual function has exclusive access among the at least one virtual function to a predetermined array of the multiple arrays of coarse-grained reconfigurable units, and wherein the reconfigurable processor is adapted for only notifying the physical function driver and the first virtual function driver about the interrupt when the predetermined event occurred in the predetermined array of the multiple arrays of coarse-grained reconfigurable units.
 10. The system of claim 1, further comprising: external memory that is that is operatively coupled to the communication link, wherein a first virtual function of the at least one virtual function has exclusive access among the at least one virtual function to a predetermined portion of the external memory, and wherein the reconfigurable processor is adapted for only notifying the physical function driver and the first virtual function driver about the interrupt when the predetermined event occurred in the predetermined portion of the external memory or during access to the predetermined portion of the external memory.
 11. The system of claim 1, wherein the reconfigurable processor further comprising: a virtualization mailbox for sending messages from the physical function to a first virtual function of the at least one virtual function, wherein the physical function generates an additional interrupt when the physical function sends a message to the first virtual function, and wherein the reconfigurable processor is adapted for only notifying the first virtual function about the additional interrupt.
 12. A method of operating a system that comprises a communication link, a runtime processor that is operatively coupled to the communication link, and a reconfigurable processor comprising multiple arrays of coarse-grained reconfigurable units, and an interface to the communication link that couples the reconfigurable processor to the runtime processor via the communication link, comprising: configuring, with the runtime processor, the interface to the communication link to provide access to the multiple arrays of coarse-grained reconfigurable units from a physical function driver and from at least one virtual function driver; generating, with the reconfigurable processor, an interrupt in response to a predetermined event; and reporting, with the reconfigurable processor, the interrupt to the physical function driver in the runtime processor and to a virtual function driver of the at least one virtual function driver in the runtime processor.
 13. The method of claim 12, wherein the reconfigurable processor further comprises storage circuitry, further comprising: storing a first identifier in the storage circuitry that identifies an array of the multiple arrays of coarse-grained reconfigurable units that generated the interrupt; and storing a second identifier in the storage circuitry that identifies the predetermined event that caused the interrupt.
 14. The method of claim 12, wherein the communication link comprises a Peripheral Component Interface Express (PCIe) bus, further comprising: with the reconfigurable processor, implementing a PCIe message signaled interrupt (MSI-X) in response to the predetermined event.
 15. The method of claim 12, wherein a first virtual function of at least one virtual function; that is associated with a first virtual function driver of the at least one virtual function driver, has exclusive access among the at least one virtual function to a predetermined array of the multiple arrays of coarse-grained reconfigurable units, further comprising: with the reconfigurable processor, only notifying the physical function driver and the first virtual function driver about the interrupt when the predetermined event occurred in the predetermined array of the multiple arrays of coarse-grained reconfigurable units.
 16. The method of claim 12, wherein the system further comprises external memory that is operatively coupled to the communication link, and wherein a first virtual function of at least one virtual function, that is associated with a first virtual function driver of the at least one virtual function driver, has exclusive access among the at least one virtual function to a predetermined portion of the external memory, further comprising: with the reconfigurable processor, only notifying the physical function driver and the first virtual function driver about the interrupt when the predetermined event occurred in the predetermined portion of the external memory or during access to the predetermined portion of the external memory.
 17. The method of claim 12, wherein the reconfigurable processor further comprises a virtualization mailbox for sending messages from a physical function that is associated with the physical function driver to a first virtual function that is associated with a first virtual function driver of the at least one virtual function driver, and wherein the physical function generates an additional interrupt when the physical function sends a message to the first virtual function, further comprising: with the reconfigurable processor, only notifying the first virtual function about the additional interrupt.
 18. A non-transitory computer-readable storage medium including instructions that, when executed by a processing unit, cause the processing unit to operate a system that comprises a communication link, a runtime processor that is operatively coupled to the communication link, and a reconfigurable processor comprising multiple arrays of coarse-grained reconfigurable units, and an interface to the communication link that couples the reconfigurable processor to the runtime processor via the communication link, the instructions comprising: configuring the interface to the communication link to provide access to the multiple arrays of coarse-grained reconfigurable units from a physical function driver and from at least one virtual function driver; generating an interrupt in response to a predetermined event; and reporting the interrupt to the physical function driver in the runtime processor and to a virtual function driver of the at least one virtual function driver in the runtime processor.
 19. The non-transitory computer-readable storage medium of claim 18, wherein a first virtual function of at least one virtual function, that is associated with a first virtual function driver of the at least one virtual function driver, has exclusive access among the at least one virtual function to a predetermined array of the multiple arrays of coarse-grained reconfigurable units, the instructions further comprising: only notifying the physical function driver and the first virtual function driver about the interrupt when the predetermined event occurred in the predetermined array of the multiple arrays of coarse-grained reconfigurable units.
 20. The non-transitory computer-readable storage medium of claim 18, wherein the system further comprises external memory that is operatively coupled to the communication link, and wherein a first virtual function of at least one virtual function, that is associated with a first virtual function driver of the at least one virtual function driver, has exclusive access among the at least one virtual function to a predetermined portion of the external memory, the instructions further comprising: only notifying the physical function driver and the first virtual function driver about the interrupt when the predetermined event occurred in the predetermined portion of the external memory or during access to the predetermined portion of the external memory. 